Imaging prevention method and system

ABSTRACT

As an imaging prevention method for interfering unauthorized imaging of a number of visual images projected on a screen, there is employed a method for projecting infrared light to a viewer/audience direction from at least one or more infrared light projector devices. According to the method, infrared light maybe directly incident into an imaging apparatus of a person conducting an unauthorized copying act so as to adversely affect the unauthorized copying.

RELATED APPLICATION DATA

This application is a divisional of application Ser. No. 10/058,688,filed on Jan. 28, 2002, which application claims the benefit ofprovisional application Ser. No. 60/291,404, filed May 16, 2001, thecontents of these applications being hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to technology for interfering unauthorizedcopy of visual images shown on a screen of a visual image system.

2. Description of the Related Art

Following technique is disclosed as means to interfere such anunauthorized copy. The technique has been developed to utilizedifference between visual characteristic of human eyes and imagecharacteristic of imaging apparatus such as cameras, and employsinfrared light to realize means to interfering the unauthorized copy.More specifically, infrared light is projected onto a screen surfacefrom an infrared light projector disposed at a vicinity of an visualimage projector or other remote position so as that infrared lightreflected on the screen surface can be incident into the imagingapparatus of a person conducting the unauthorized act of copying thevisual image appearing on the screen. In other words, an infrared lightvisual image, which is irrelevant to the main feature of visual images,is inevitably recorded on the visual image that is obtained in theunauthorized manner. Accordingly, overall quality of visual imagesrecorded through the unauthorized manner are degraded. Sometime, such adegraded visual image enables to determine a location where theunauthorized act is taken place. Of course, viewer/audiences would notbe affected by the interfering means and can enjoy the featurepresentation of visual images appeared on the screen since infraredlight can not be recognized by human eyes.

SUMMARY OF THE INVENTION

However, a reflection ratio of infrared light in a conventional cinemascreen is not high enough. Accordingly, it is difficult to materializedesirable effect in a conventional system described above because of thelow reflection ratio in the cinema screen as well as lengthy infraredlight path between the screen and the infrared light projector disposedat the vicinity of the visual image projector. Further, there is atechnical problem of that relatively high output power is required forthe infrared projector so as to provide any significant effects on thevisual images that are illegally recorded.

The present invention addresses the above-mentioned problems. It wouldbe desirable to provide a practical technique capable of producing equalor more effective prevention effect than the conventional one whileusing an infrared light projector apparatus of a lower power.

According to the present invention, following means are provided.

(A) As a first means, the following technique is provided. In thetechnique, infrared light is projected to a viewer/audience directionfrom one or more infrared light projector means disposed at a screenside whereby enabling the infrared light to be incident into imagingmeans of a person conducting the unauthorized act. In embodiments of thepresent invention, the infrared light projector means may be realized invarious configurations that include an infrared light projectorapparatus, an infrared light projector, an infrared light emitting diodeor any other device/apparatus/system capable of projecting infraredlight. Furthermore, in embodiment of the present invention, the imagingmeans may be a camera, camcorder, video recorder or any otherdevice/system comprising an image sensor capable of obtaining imagedata. The technique will eliminate needs of reflecting infrared lightprojected onto a screen surface of poor reflection ratio. Accordingly,the projected infrared light may be effectively incident into theimaging means of a person conducting the unauthorized act. That is,ample intensity of the infrared light may be radiated into the imagingmeans even when the low power infrared light projector apparatus isused.

(B) As a second means, another technique is provided. In the anothertechnique, infrared light is actively reflected by an infrared lightreflection means so as that the reflected infrared light may be incidentinto imaging means of a person conducting the unauthorized act. Inembodiments of the present invention, the infrared light reflectionmeans may be an infrared light mirror or any otherdevice/apparatus/member capable of reflecting infrared light. Thetechnique also will eliminate needs of reflecting infrared lightprojected onto a screen surface of poor reflection ratio. Accordingly,the projected infrared light may be effectively incident into theimaging means of a person conducting the unauthorized act. That is,ample intensity of the infrared light may be incident into the imagingmeans even when the low power infrared light projector apparatus isused.

(C) As a third means, still another technique is provided. In the stillanother technique, infrared light is intermittently emitted instead ofcontinuous emission. Various advantages are realized by the intermittentemission. For example, a location in which the visual image piracy wastaken place may be identified in case that the infrared lightintermittent emission is outputted in accordance with a predeterminedinformation. Alternatively, an emission intensity of infrared light maybe frequently changed whereby enabling to degrade quality of visualimages illegally recorded so much as that viewing of visual imagesrecorded in the unauthorized manner becomes impossible due to the rapidchange of intensity level.

(D) As a fourth means, still another technique is provided. In the stillanother technique, infrared light is selectively projected onto an areaor areas of the screen surface, in which brightness is lower (forexample, area or time period having a brightness of the screen surfaceequal or less than a predetermined value). The technique allows to emitor increase an amount of infrared light in a part where an amount of thevisual image light is low whereby enabling to increase relative effectsof the infrared light. Accordingly, more effective prevention of thevisual image piracy may be possible. Further, in case that certaininformation is superposed on the infrared light, such information issurely recorded on the visual images illegally recorded.

(E) As a fifth means, still another technique is provided. In the stillanother technique, infrared light is projected from a plurality ofinfrared light projector means disposed in the vicinity of a screenwhereby having the reflected infrared light be incident into imagingmeans of a person conducting the unauthorized act. The technique usesthe similar principle as that of the conventional technique except theinfrared light projector apparatus in the present embodiment areselectively disposed in the vicinity of the screen. Accordingly, thereflected infrared light may be significantly increased whereby enablingto promote the prevention effect further.

BRIEF DESCRIPTION OF THE DRAWINGS

The other objects, features and advantages of the present invention willbecome more apparent from the following description of the presentlypreferred exemplary embodiments of the invention taken in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a schematic diagram illustrating one embodiment (part 1)wherein infrared light is projected to a viewer/audience direction froma rear side of a screen;

FIG. 2 is a schematic diagram illustrating a theater screen;

FIG. 3 is a schematic diagram illustrating one embodiment (part 2)wherein infrared light is projected to a viewer/audience direction froma rear side of a screen;

FIG. 4 is a schematic diagram illustrating one embodiment whereininfrared light is projected to a viewer/audience direction from a frontside of a screen;

FIG. 5 is a schematic diagram illustrating one embodiment (part 1)wherein infrared light is projected to a viewer/audience direction froma vicinity of a screen;

FIG. 6 is a schematic diagram illustrating one embodiment (part 2)wherein infrared light is projected to a viewer/audience direction froma vicinity of a screen;

FIG. 7 is a schematic diagram illustrating one embodiment whereinreflection means of high reflection ratio for infrared light isemployed;

FIG. 8 is a schematic diagram illustrating an example of actuatorapparatus for the reflection means of high reflection ratio;

FIG. 9 is a schematic diagram illustrating one embodiment whereininfrared light is emitted intermittently;

FIG. 10 is a schematic diagram illustrating an example of emissionpattern (part 1) for a case in which infrared light is emittedintermittently;

FIG. 11 is a schematic diagram illustrating an example of emissionpattern (part 2) for a case in which infrared light is emittedintermittently;

FIG. 12 is a schematic diagram illustrating an example of emissionpattern (part 3) for a case in which infrared light is emittedintermittently;

FIG. 13 is a schematic diagram illustrating an example of emissionpattern (part 4) for a case in which infrared light is emittedintermittently;

FIG. 14 is a schematic diagram illustrating an example of emissionpattern (part 5) for a case in which infrared light is emittedintermittently;

FIG. 15 is a schematic diagram illustrating one embodiment (part 1)wherein infrared light is selectively projected onto scene or area inthe screen of low brightness;

FIG. 16 is a schematic diagram illustrating an example of an infraredlight projector apparatus having a unit configuration;

FIG. 17 is a schematic diagram illustrating an example of configurationof a film projector apparatus;

FIG. 18 is a schematic diagram illustrating relationship between shutteroperation and projection operation of infrared light;

FIG. 19 is a schematic diagram illustrating an example of shutter sensorarrangement;

FIG. 20 is a schematic diagram illustrating an example of emissioncontrol for an infrared light projector apparatus having a unitconfiguration;

FIG. 21 is a schematic diagram illustrating one embodiment (part 2)wherein infrared light is selectively projected onto scene or area inthe screen of low brightness;

FIG. 22 is a schematic diagram illustrating one embodiment whereininfrared light from a vicinity of a screen; and

FIG. 23 is a schematic diagram illustrating an example of configurationof an infrared light projector apparatus attached with an projectiondirecting actuator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(A) Conceptual Embodiment

First, conceptual embodiments of a imaging prevention method and systemin accordance with the present invention will now be described.

(1) As a method for interfering unauthorized imaging of visual imagesprojected onto a screen, the following is provided. The method comprisesthe steps of: disposing at least one or more infrared light projectormeans at a rear side of the screen or the other side of the screen fromthe viewer/audiences; and projecting infrared light from the at leastone or more infrared light projector means to a viewer/audiencedirection whereby enabling the infrared light to enter an imaging meansof a person conducting the unauthorized act.

The method will eliminate needs of reflecting infrared light at a screensurface of poor reflection ratio. Accordingly, the projected infraredlight may be effectively incident into the imaging means of a personconducting the visual image piracy. Further, ample intensity of theinfrared light may be radiated into the imaging means even when the lowpower infrared light projector means is used.

Various methods for projecting infrared light may be contemplated. Forexample, the various methods may include a method for projectinginfrared light by letting at least a part of the infrared light passthrough space besides the screen, a method for projecting infrared lightby transmitting at least a part of the infrared light through thescreen, or a method for projecting infrared light by letting at least apart of the infrared light pass through a pass-through part disposed inthe screen.

Here, remarkably high prevention effect is expected for the firstexample or the third example since there is no factor of drasticallyreducing an amount of light in cases where the infrared light isdirectly incident into the imaging means.

Further, the first example include such a case in which the infraredlight is reflected by an object other than the screen. The object mayhave a high reflection ratio for the infrared light and may be, forexample, a wall or an infrared light reflection mirror so called a hotmirror. Alternatively, the object that reflects the infrared light maybe one that scatters the infrared light. In the following, the object isthe same as ones reflecting the infrared light.

As the pass-through part in the third example, a construction such as acut or gap extending to one direction (e.g. slit), a hole part throughthe screen (e.g. small hole or bore), or any other construction in whichthe infrared light may pass through the screen from the rear side to thefront side may be contemplated. Here, it is preferred to have one ormore pass-through parts in the screen. In general, stronger infraredlight is output toward the front side of the screen as more number ofthe pass-through parts are provided. Further, the pass-through parts maybe distributed uniformly on a whole screen area or concentrated in aparticular area (e.g. screen center part or screen peripheral part).

On the other hand, significant prevention effect is expected for case,like the second example, where the infrared light passed through thescreen may be incident into the imaging means for some screenconstruction types. Particularly, sufficient prevention effect isexpected for a type in which an original visual image is projected frombehind the screen since it is expected high transmission ratio of theinfrared light is also high.

For the second example, followings may be used. The means include ascreen having an area of transmitting the infrared light with a thinnermember part compared to the other part of the screen (for example, aconcaved part) thereby enabling easily transmission of the infraredlight, a method for varying a member which easily transmits the infraredlight and letting the infrared light pass the member, or a screencomprising members that easily pass the infrared light.

In any of the above-described examples, a projection direction of visualimage onto the screen may be either a direction from the viewer/audienceside to the screen or a direction from the rear side of the screenviewing from the viewer/audience to the screen side (viewer/audiencedirection). The same applies to the following other methods.

(2) As one of methods for interfering unauthorized imaging of visualimage projected on a screen, the following technique is provided. In thetechnique, infrared light is projected to a viewer/audience directionfrom one or more infrared light projector means disposed at a front sideof the screen viewing from the viewer/audience side whereby enabling theinfrared light to be incident into imaging means of a person conductingthe unauthorized act.

The method will eliminate needs of reflecting infrared light projectedonto a screen surface of poor reflection ratio. Accordingly, theprojected infrared light may be effectively incident into the imagingmeans of a person conducting the unauthorized act. Further, more ampleamount of the infrared light may be incident into the imaging meanscompared to that of the previous method since there is almost nointerfering object exist in between the infrared light projector meansand the imaging means as well as the infrared light may be projectedfrom close vicinity of a person conducting the unauthorized act.

A projection direction of the infrared light projector means may befixed or varied automatically. The projection direction, that may bevariably set, may include a particular direction (not only singledirection but also a plurality of directions) or any arbitrarydirection. By varying the projection direction, it becomes possible toeliminate space that could allow the unauthorized imaging act. The sameapplies to the other methods.

Further, when the infrared light projector means and the infrared lightreflection means are used in combination, the infrared light may beprojected to a wider area similar to the previous case described abovein case that at least one of means is capable of varying the projectiondirection or the reflection direction. Further, this method does notexclude use of an object having a high infrared light reflection ratio,such as a wall or infrared light reflection mirror.

(3) As a method for interfering unauthorized imaging of visual imageprojected on a screen, the following is provided. In the method,infrared light is directly projected to a viewer/audience direction fromone or more infrared light projector means disposed in a vicinity of thescreen whereby enabling the infrared light to be incident into imagingmeans of a person conducting the unauthorized act.

The method also will eliminate needs of reflecting infrared lightprojected onto a screen surface of poor reflection ratio. Accordingly,the projected infrared light may be effectively incident into theimaging means of a person conducting the unauthorized act. Further, inthis method, more ample amount of the infrared light may be incidentinto the imaging means compared to the method of (1) since there isalmost no interfering object exist in between the infrared lightprojector means and the imaging means as well as the infrared light maybe projected from close vicinity of a person conducting the unauthorizedact.

Here, in the vicinity of the screen, not only space along outerperiphery of the screen but also space extending outward from the outerperiphery are included. Further, space in the vicinity of the screen isnot necessary to be the same plane of the screen in strict sense. It issupposed that the vicinity of the screen may be positioned at a frontside or back of a hypothetical plane including the screen with having acertain amount of distance in between.

(4) As a method for interfering unauthorized imaging of visual imageprojected on a screen, the following is provided. In the method,infrared light, that is projected from at least one or more infraredlight projector means, is reflected to a viewer/audience directionwhereby enabling the infrared light to be incident into imaging means ofa person conducting the unauthorized act.

The method does not use a screen surface of poor reflection ratio as thereflection means. Instead, it uses the infrared light reflection meanswith the high reflection ratio whereby enabling more ample amount of theinfrared light to be incident into the imaging means of a personconducting the unauthorized act. Accordingly, it becomes possible torealize lowering of output of the infrared light projector means.

Here, the infrared light reflection means may be disposed in anyarbitrary position. For example, it may be disposed in a front side ofthe screen viewing from the viewer/audience side, or in a rear side ofthe screen, or in the vicinity of the screen. In any case, it is desiredthat the position may be one from which ample amount of the infraredlight incident into the imaging means of a person conducting theunauthorized act.

Further, the infrared light reflection means or its reflection surfacemay be configured as that its reflection direction is varied arbitraryby actuator means. By utilizing such infrared light reflection means, anarea, in which the infrared light prevention is possible, may beexpanded compared to that of the fixed reflection direction.

Further, the infrared light reflection means may be, for example, aninfrared light reflection mirror. Such member may be in a film form orany other predetermined forms with arbitrary thickness.

(5) As a method for interfering unauthorized imaging of visual imageprojected on a screen, the following is provided. In the method, aninfrared light is intermittently emitted from at least one or moreinfrared light projector means whereby enabling predeterminedintermittent emission pattern to be recorded on imaging means of aperson conducting the unauthorized act.

The method enables to record the intermittent emission patternirrelevant to the present feature of program on visual images recordedin the unauthorized manner by intermittently emitting the infraredlight. Recorded pattern of the intermittent light differs depending onin what form the infrared light incident into the imaging means.

For example, in case in which scattered light of the infrared lightwhich light flux is uniformly spread out is incident, an emissionintensity of infrared light may be frequently changed whereby enablingto degrade quality of visual images so much as that viewing becomesdifficult. Further, for another example, in case in which spread oflight flux is limited to a certain size (including pin point size), anintensity of infrared light may be frequently changed at a part of thescreen. This case similarly enables to degrade quality of visual imagesso much as that viewing becomes difficult.

Further, it is obvious that this emission control method may be combinedwith the above described methods (1)-(4). That is, the infrared lightprojector means may be disposed at any arbitrary location. It is alsopossible to combine this method with the method in which the infraredlight reflection means actively reflect. Alternatively, followingmethods may be possible for controlling the infrared light emission.

(5a) Method for controlling at least one or more infrared lightprojector means based on predetermined code information to emitintermittently so as to record information along time axis direction:

This method superimposes information on the emission timing itself Thatis, prescribe information (for example, output date/time, outputlocation, screen number (number uniquely identifiable of each screen),output apparatus, a person performing output, and any other informationrequired to identify a location where the unauthorized act is conducted)is forced to be recorded as point image pattern in binary form. Ofcourse, it is also possible to prevent the viewing by the intermittentemission itself.

When a plurality of the infrared light projector means are used, all ofthem may be turned on/off at the same time, or emitting position may bechanged in sequence in relay form like (5b) while the emission timingitself may be controlled as the same way as a case in which only singleinfrared light projector means is used. Further, the emitting positionmay be randomly changed or changed in sequence in accordance with apredetermined rule when the plurality of the infrared light projectormeans are used.

(5b) Method for controlling plural infrared light projector means basedon predetermined code information to emit intermittently in relay formso as to record information along time axis direction:

Although this method may be applicable to a case in which the emissiontiming itself compose meaning like in the case of (5a) (no meaning in aposition of the light image), the method enables to superimpose desiredinformation in light image positions themselves to be recorded. Forexample, a following method may be applicable. In the method, the lightimage position may be changed in accordance with a series of binary datarepresenting the desired information when two light image positions areprovided wherein “1” of the binary data is assigned to one of thepositions and “0” of the binary data is assigned to the other. Ofcourse, it is also possible to prevent the viewing by the intermittentemission itself. Further, the desired information may be forced to berecorded without affecting the viewing of the viewer/audience (only aneffect comparable to natural noise will be recognized by many of theviewer/audiences) when area size of the recorded light image is small.

(5c) Method for controlling plural infrared light projector means basedon predetermined code information to emit intermittently in relay formso as to record two-dimensional information:

In this method, positions at which the light images appeared arecompressed along the time axis direction to compose single plane so asto reveal the recording of a two dimensional information (figure, codeor any other recognizable shape). For example, the method may definecorrespondences between the light image position itself and theinformation by dividing the screen into four sections and by assigningone theater a pattern in which the light image appears on all of thefour sections and another theater another pattern in which the lightimage appears on three sections except the upper right section. Further,it is also possible to vary two dimensional information on a transitiontrajectory of the light image positions. For example, it is possible toconfigure so as that a two dimensional information may be appeared whenthe light image is traced as it appeared. Alternatively, it is alsopossible to superimpose the information in the light image transitiondirection itself.

(5d) Method for controlling plural infrared light projector means toemit in predetermined combination so as to record two-dimensionalinformation:

The method enables to instantly identify the light images dispersed inthe time axis direction as in (5c) on the same screen. For example, itis possible to associate the plural light images with a bar codepattern. Alternatively, more information may be recorded by associatingpatterns (graphical pattern) representative of the light images withmulti-valued code information and changing the displaying pattern alongthe time axis direction. This method is a composite method for combininginformation along the time axis and information in two dimensionaldirection.

(5e) Method for disposing at least one or more infrared light projectormeans comprising an array of light emitting devices at a rear side ofthe screen viewing from a viewer/audience side, and controllingindividual light emitting device to generate an emission pattern of theinfrared light whereby enabling a predetermined information to berecorded in imaging means of a person conducting the unauthorized act:

This method is similar to embodiment (5d) except the infrared lightprojector means comprises plural light emitting devices and thedisposing location of the infrared light projector means is at behindthe screen. Information may be displayed on the same screen in ainstantly recognizable form even by controlling the emission by eachlight emitting device. Of course, more information may be recorded byassociating patterns (graphical pattern) representative of the lightimages with multi-valued code information and changing the displayingpattern along the time axis direction. Alternatively, the method may beconfigured so as that predetermined information is displayed byutilizing only the emission of plural light emitting devices arrayed inthe same infrared light projector means or the predetermined informationis displayed by utilizing the emissions of combined light emittingdevices, each set of the devices being arrayed in different infraredlight projector means.

(6) As a method for interfering unauthorized imaging of visual imageprojected on a screen, the following is provided. In the method,brightness at a screen surface is detected by at least one or more lightsensors facing the screen surface and being disposed behind the screenviewing from viewer/audience side, and an amount of infrared lightprojected from an infrared light projector means is increased as thedetected brightness of the screen surface decrease.

This method is a method for increasing the amount of the infrared lightprojected onto a scene or area of the screen surface having the lowbrightness. By using this method, the amount of the infrared light islowered when the brightness of the screen surface is high (screen isbright) and thus prevention effect of the infrared light is small, andthe amount of the infrared light is increased when the brightness of thescreen surface is low (screen is dark) and thus prevention effect of theinfrared light is large. Accordingly, the prevention effect is highercompared to a case in which the same amount of the infrared light isconstantly emitted or the infrared light is projected uniformly over awhole screen surface.

The infrared light projector means may be disposed in an arbitraryposition. Further, as regarding which path the infrared light shouldfollow to enter the imaging means of a person conducting theunauthorized act, the path requiring reflection on the screen, the pathfor direct incident through space other than the screen, or the pathpassing through or transmitting through the screen is possible. Ofcourse, it is possible to combine this method with the above describedmethods (1)-(5).

(6a) Method for detecting brightness at a screen surface with at leastone or more light sensors that are disposed behind the screen viewingfrom viewer/audience side and facing the screen surface, and projectinginfrared light from at least one or more infrared light projector meanswhen the detected brightness of the screen surface is equal or less thana predetermined brightness whereby enabling the infrared light to beincident into an imaging means of a person conducting an unauthorizedact:

This method enables to increase the relative brightness level of theinfrared light with respect to the visual image of the main featureprogram, and to effectively amplify the effect of the infrared lightsince the infrared light is projected onto the screen surface during thedark scene or the dark period. Accordingly, the ample effect may begenerated with the infrared light projector means with a low outputpower. Also in this case, the infrared light projector means may bedisposed any arbitrary position. It is possible to contemplate that aroute of the infrared light to be incident into the imaging means of aperson conducting the unauthorized act may be one requiring reflectionat the screen, one passing through space other than the screen to directincident, one passing or transmitting through the screen, or the like.Of course, it is possible to combine this method with the above-citedmethods (1)-(5).

Further, it is possible to select the vicinity of screen center as aportion in which brightness of the screen is to be determined. A lightimage of the infrared light may be visualized more clearly by emittingthe infrared light when the brightness at the vicinity of screen centeris low. Accuracy of determination of whether the visual image is dark orbright may increase in case that a plurality of the detection resultsare used and the infrared light is projected when a predetermined numberof the detection results, in which brightness of the screen surface isdetected to be equal or less than a predetermined brightness, aredetected, so as to promote reliability. Alternatively, an average valueof the plural detection results may be set as the brightness of thescreen surface and compared with a threshold value.

Here, “the predetermined brightness”, that is the threshold value fordetermining the screen brightness, may be fixed independent of thevisual images projected on the screen or varied to be a different valuedepending on the visual image. Alternatively, the predeterminedbrightness may be independently adjusted by a manager side in acommercial system such as a movie theater. In this case, a functiondisabling an adjustment to a value equal or less than a predeterminedbrightness may be employed as a safety measure whereby enabling tocountermeasure an ill-intentioned manager. Alternatively, thepredetermined brightness may be controlled in accordance with aninstruction from a content-provider side connected via a network. Ofcourse, such instruction may also be notified off-line.

Further, “the predetermined number”, that is the threshold value fordetermining whether the infrared light should be projected or not, mayinclude a number “one”. In general, the accuracy of determinationincreases as the threshold value for determination increases. Thepredetermined number may also be independently adjusted by a managerside in a commercial system such as a movie theater. In this case, theinfrared light is constantly emitted when no detection result isinputted (case of NO SIGNAL) as well as a function disabling anadjustment to a value more than the number of detection results to beused for the determination may be employed as a safety measure wherebyenabling to countermeasure an ill-intentioned manager. Furthermore, thepredetermined value may also be controlled in accordance with aninstruction from a content-provider side connected via a network. Ofcourse, such instruction may also be notified off-line.

Here, the emission of the infrared light may be an emission thatgenerates a light image to-be-recorded extending to a whole area of thescreen or a light image extending only to a portion or multiple portionsof the screen. The following methods may be contemplated as a method forcontrolling the emission of the infrared light.

(6b) Method for detecting brightness at a screen surface with at leastone or more light sensors facing the screen, and individually projectinginfrared light from at least one or more infrared light projector meansin case that the brightness of the screen surface is equal or less thana predetermined brightness whereby enabling the infrared light to beincident into imaging means of a person conducting an unauthorized act,wherein the at least one or more light sensors are disposed behind thescreen viewing from a viewer/audience side, and the infrared lightprojector means projecting the infrared light is associated with an areacorresponding to the light sensor detecting the brightness equal or lessthan the predetermined brightness:

This method enables to adaptively project the infrared light ontopartial area(s) of the screen surface, in which the brightness is low,whereby enabling the recording of light images of the infrared light atcorresponding partial area(s). With utilizing the method, it would bedifficult to view the visual images recorded in the unauthorized waysince the infrared light is recorded onto the partial area with the lowbrightness. Of course, it is possible to combine this method with theabove-cited methods (1)-(5).

(6c) Method for reproducing time information, in which brightness at ascreen becomes equal or less than a predetermined brightness value, froma recording medium, and projecting infrared light from at least one ormore infrared light projector means in accordance with the reproducedinformation whereby enabling the infrared light to be incident into animaging means of a person conducting an unauthorized act:

This method is not to control the infrared light emission in real-timebased on the detection results of actual measurements, but a method forcontrolling the infrared light emission based on the informationprovided from a distributor of the main feature program or a provider orthe like. That is, the method obtains the information of method (6) fromthe recording medium and requires no light sensor or the like.

The recording medium to be read may be ones recording informationrequired for the emission control of the infrared light distributed fromthe distributor or the provider to the projector side as well as onesused for recording information received by the projector side via anetwork. Of course, it is possible to combine this method with theabove-cited methods (1)-(5).

(6d) Method for reproducing area and time information, in whichbrightness at a screen becomes equal or less than a predeterminedbrightness value, from a recoding medium, and individually projectinginfrared light from at least one or more infrared light projector meansassociated with corresponding areas on the screen in accordance with thereproduced information whereby enabling the infrared light to beincident into an imaging means of a person conducting an unauthorizedact:

This method does not control the infrared light emission based on thereal-time detection results. Instead, the method is a method forcontrolling the infrared light emission based on the informationprovided from the distributor of the main feature program or theprovider or the like. With employing such method, it is also possible toattain an object of enabling the record of the infrared light image atthe partial areas by adaptively projecting the infrared light to thescreen surface at the partial areas having the low brightness. Ofcourse, it is possible to combine this method with the above-citedmethods (1)-(5).

(6e) Method for receiving information from a network for time in whichbrightness at a screen becomes equal or less than a predeterminedbrightness value in synchronization with a projection of visual images,and individually projecting infrared light from at least one or moreinfrared light projector means in accordance with the receivedinformation whereby enabling the infrared light to be incident into animaging means of a person conducting an unauthorized act:

This method is a method for acquiring information relating to method (6)via the network and controlling the infrared light emission. Withemploying such method, it is also possible to attain an object ofenabling the record of the infrared light image at the time periods byadaptively projecting the infrared light to the screen surface at thetime periods having the low brightness. The information may be receivedin synchronization with the output of visual images when the projectionof the main feature program to the screen is performed only once. Whenthe output of the main feature program is repeated plural times, thepredetermined information (information indicating time periods in whichbrightness of the screen becomes equal to or less than the predeterminedbrightness value) may be received every time the output is performed.Alternatively, it is also possible to acquire the predeterminedinformation in real-time for the first time and use the informationrecorded when it was received for the first time for the subsequentoutputs. Of course, it is also possible to combine this method with theabove-cited methods (1)-(5).

(6f) Method for receiving information from a network for area and timein which brightness at a screen becomes equal or less than apredetermined brightness value in synchronization with a projection ofvisual images, and individually projecting infrared light from at leastone or more infrared light projector means associated with correspondingareas on a screen in accordance with the received information wherebyenabling the infrared light to be incident into an imaging means of aperson conducting an unauthorized act:

This method is a method for acquiring information relating to method(6c) via the network and controlling the infrared light emission. Withemploying such method, it is also possible to attain an object ofenabling the record of the infrared light image at the partial areas byadaptively projecting the infrared light to the screen surface at thepartial areas having the low brightness. The information may be receivedin synchronization with the output of visual images when the output ofthe main feature program to the screen is performed only once. When theoutput of the main feature program is repeated plural times, thepredetermined information (information indicating area and time in whichbrightness of the screen becomes equal to or less than the predeterminedbrightness value) may be received every time the output is performed.Alternatively, it is also possible to acquire the predeterminedinformation in real-time for the first time and use the informationrecorded when it is received in the first time for the subsequentoutputs. Of course, it is also possible to combine this method with theabove-cited methods (1)-(5).

(6g) Method for projecting infrared light from at least one or moreinfrared light projector means during a period of shielding theprojection light with a frame transferring shutter when the visual imageis projected from a film type projector means whereby enabling theinfrared light to be incident into an imaging means of a personconducting an unauthorized act:

This method is a unique one for a case when the film type projection isutilized. Namely, the present embodiment is focused on features ofclosing the frame transferring shutter so as to shield the projectionlight when the film frame is transferred. The present embodiment ensuresthe recording of the infrared light image by projecting the infraredlight during a period when the frame transferring shutter has beenclosed for considering a decrease of the screen surface brightness. Withutilizing such method, it is possible to accomplish an object ofrecording the infrared light image. The period of shielding theprojection light with the frame transferring shutter may be detected orpredicted from a frame transferring motion, or may be detected orpredicted from a motion of the frame transferring shutter. Of course, itis also possible to combine this method with the above-cited methods(1)-(5).

(7) As a imaging prevention method for interfering unauthorized imagingof visual image projected on a screen, the following is provided. Themethod is for projecting infrared light from at least one or moreinfrared light projector means disposed in a vicinity of the screenwhereby enabling the infrared light reflected on the screen to incidentinto an imaging means of a person conducting the unauthorized act.

This method shares the same principle as an conventional system onfeatures wherein the infrared light is projected toward the screen fromthe vicinity of the screen front whereby enabling the reflected infraredlight at the screen to incident into the imaging means of a personconducting the unauthorized act. However, in this method, the disposinglocation of the infrared light projector means is optimized and set tothe vicinity of the screen so as to increase an amount of the infraredlight reflected at the screen surface remarkably with respect to theconventional system.

With employing this configuration, the technical effect substantiallythe same as that of the conventional system may be obtained by using theinfrared light projector means with less output. If the infrared lightprojector means with substantially the same output as that of theconventional system is utilized, far greater prevention effect may beobtained. In general, a greater prevention effect may be obtained byusing a less output infrared light projector means.

(8) As an imaging prevention method for interfering unauthorized imagingof visual image projected on a screen, the following is provided. Themethod is for automatically adjusting a projection direction of at leastone or more infrared light projector means disposed in a vicinity of thescreen in correspondence with size change of the screen, and projectinginfrared light to the adjusted projection direction whereby enabling theinfrared light reflected on the screen to incident into an imaging meansof a person conducting the unauthorized act.

This method enables to secure the projection direction optimized inaccordance with the screen size by automatically adjusting the infraredlight projection direction (projection position of the infrared lightprojected on the screen) coupled with the screen size change.Particularly, it is more important for the infrared light projectormeans projecting to a corner portion of the screen since there is apossibility of that the infrared light may not be contributed in theprevention of the unauthorized act when the screen size is changed. Theadjustment may be performed manually. According to the presentembodiment, an operational efficiency may be improved since an operatoronly has to consider the screen size change. The infrared lightprojector means is not limited to ones disposed in the vicinity of thescreen.

(9) As a system for interfering unauthorized imaging of visual imagesprojected onto a screen, the following is provided. In the system, atleast one or more infrared light projector means are disposed at a rearside of the screen viewing from viewer/audiences and infrared light isprojected from the at least one or more infrared light projector meansto a viewer/audience direction whereby enabling the infrared light toenter an imaging means of a person conducting the unauthorized act.

This system corresponds to the above-cited method (1). That is, thesystem enables to project infrared light from the rear side of thescreen and enables the infrared light to efficiently enter the imagingmeans of a person conducting the unauthorized act without requiring thereflection at the screen surface. The description of (1) also applies tothis system.

(10) As a system for interfering unauthorized imaging of visual imagesprojected onto a screen, the following is provided. In the system, atleast one or more infrared light projector means are disposed at a frontside of the screen viewing from viewer/audiences and infrared light isprojected from the at least one or more infrared light projector meansto a viewer/audience direction whereby enabling the infrared light todirectly enter an imaging means of a person conducting the unauthorizedact.

This system corresponds to the above-cited method (2). That is, thesystem enables to project infrared light from the front side of thescreen and enables the infrared light to efficiently enter the imagingmeans of a person conducting the unauthorized act without requiring thereflection at the screen surface. The description of (2) also applies tothis system.

(11) As a system for interfering unauthorized imaging of visual imagesprojected onto a screen, the following is provided. In the system, atleast one or more infrared light projector means are disposed in avicinity of the screen and infrared light is projected from the at leastone or more infrared light projector means to a viewer/audiencedirection whereby enabling the infrared light to enter an imaging meansof a person conducting the unauthorized act.

This system corresponds to the above-cited method (3). That is, thesystem enables to project infrared light from in the vicinity of thescreen and enables the infrared light to enter the imaging means of aperson conducting the unauthorized act without requiring the reflectionat the screen surface. The description of (3) also applies to thissystem.

(12) As a system for interfering unauthorized imaging of visual imagesprojected onto a screen, the following is provided. The system comprisesat least one or more infrared light projector means for projectinginfrared light, and infrared light reflection means for reflectinginfrared light projected from the at least one or more infrared lightprojector means so as the infrared light directly incident into animaging means of a person conducting the unauthorized act.

This system corresponds to the above-cited method (4). That is, thesystem enables to increase an amount of the infrared light entering tothe imaging means of a person conducting the unauthorized act byutilizing the infrared light reflection means actively reflecting theinfrared light. The description of (4) also applies to this system.

A driving technique of driving means for variably controlling theinfrared light reflection means or its reflection surface may not belimited to particular ones. Further, it is not necessary to control thereflection surface of the infrared light reflection means so as that awhole area of the reflection surface is directed to the same direction.Alternatively, when the reflection surface is divided into a plural ofsections and each of the sections is independently controllable, each ofthe sections may be controlled to direct a different direction.

(13) As a system for interfering unauthorized imaging of visual imagesprojected onto a screen, the following is provided. The system comprisesat least one or more infrared light projector means for projectinginfrared light, and emission control means for controlling the at leastone or more infrared light projector means to emit intermittently so asan imaging means of a person conducting the unauthorized act records apredetermined pattern of the intermittent emission.

This system corresponds to the above-cited method (5). That is, thesystem enables to force recording of the emission pattern irrelevant tothe main feature of the program illegally recorded by intermittentlyemitting the infrared light. The description of (5) also applies to thissystem.

The emission control means may be, for example, an electronic circuitsuch as a computer, an IC for specific purpose, switching means forswitch-controlling the emission according to a clock or its dividedfrequency output, switching means for switch-controlling the emissionaccording to charging/discharging of a capacitor or the like, or,switching means for switch-controlling the emission by a mechanicalstructure or the like. Of course these function may be realized withusing software or hardware. This system may include systemscorresponding to methods (5a)-(5e).

(13a) System utilizing emission control means for enabling at least oneor more infrared light projector means to emit intermittently inaccordance with a predetermined code information so as that an imagingmeans of a person conducting the unauthorized act records informationalong a time axis, instead of using the emission control means of (13):

This system corresponds to the above-cited method (5a). That is, in thissystem, the information is superposed on the emission timing itself. Thedescription of (5a) also applies to this system.

(13b) System utilizing emission control means for controlling aplurality of infrared light projector means to emit intermittently inrelay format in accordance with a predetermined code information so asthat an imaging means of a person conducting the unauthorized actrecords information along a time axis, instead of using the emissioncontrol means of (13):

This system corresponds to the above-cited method (5b). That is, in thissystem, the emission timing itself may have meanings in some case, andit is also possible to superpose the desired information on locations ofthe recorded light images themselves. The description of (5b) alsoapplies to this system.

(13c) System utilizing emission control means for controlling aplurality of infrared light projector means to emit intermittently inrelay format in accordance with a predetermined code information so asthat an imaging means of a person conducting an unauthorized act recordsa two-dimensional information, instead of using the emission controlmeans of (13):

This system corresponds to the above-cited method (5c). That is, thesystem enables to clearly ascertain the record of the two-dimensionalinformation (figure, notation, or any other identifiable forms) whenlight image positions are compressed in the time-axis direction. Thedescription of (5c) also applies to the system.

(13d) System utilizing emission control means for controlling aplurality of infrared light projector means to emit intermittently in apredetermined combination so as that an imaging means of a personconducting the unauthorized act records a two-dimensional information,instead of using the emission control means of (13):

This system corresponds to the above-cited method (5d). That is, thesystem enables to ascertain the record of light images in all locations,that are spread in the time axis direction in the above-cited (13c), atthe same display screen simultaneously by lighting them up altogether.The description of (5d) also applies to this system.

(13e) System utilizing at least one or more infrared light projectionunit comprising a plurality of light emitting devices disposed in anarray for projecting infrared light, and an infrared light projectioncontrol unit for individually controlling said light emitting device ofthe infrared light projector means disposed in a rear side of the screenviewing from a viewer/audience side so as that an imaging means of aperson conducting an unauthorized act record a predetermined informationcorresponding to an emission pattern of the infrared light:

This system corresponds to the above-cited method (5e). That is, thissystem is similar to embodiment (13d). Of course, the description of(5d) also applies to the system. Further, the infrared light projectioncontrol unit may be, for example, an electronic circuit such as acomputer, an IC for specific purpose, switching means forswitch-controlling the emission according to a clock or its dividedfrequency output, switching means for switch-controlling the emissionaccording to charging/discharging of a capacitor or the like, or,switching means for switch-controlling the emission by a mechanicalstructure or the like.

(14) As an imaging prevention system for interfering unauthorizedimaging of visual image projected on a screen, the following isprovided. The system comprises at least one or more infrared lightprojector means for projecting infrared light, and at least one or morelight sensors disposed in a rear side of the screen viewing from aviewer/audience side for detecting brightness of the facing screen,wherein a detection result of the light sensor is outputted to thecorresponding infrared light projector means as a light amount adjustingsignal for increasing an amount of the infrared light as the detectedbrightness of the screen surface decrease.

This system corresponds to the above-cited method (6). That is, thissystem enables to adaptively increase the amount of the infrared lightprojected onto a scene or area of the screen surface having the lowbrightness whereby enabling the infrared light to be easily recorded onan imaging means of a person conducting an unauthorized act. Thedescription of (6) also applies to this system.

For example, a photo-diode or a photo-transistor may be employed for thelight sensor. Further, this system may include systems corresponding tomethods (6a)-(6g).

(14a) As an imaging prevention system for interfering unauthorizedimaging of visual image projected on a screen, the following system isprovided. The system comprises at least one or more infrared lightprojector means for projecting infrared light, at least one or morelight sensors disposed close to a backside of the screen viewing from aviewer/audience side, and an infrared light projection control unit foraccepting output signals from the light sensors and for controlling theat least one or more infrared light projector means to project theinfrared light in case that a brightness of the screen surface facingthe light sensor is equal or less than a predetermined brightness.

This system corresponds to the above-cited method (6a). That is, thissystem enables to project the infrared light onto a scene or area of thescreen surface having the low brightness based on the detection resultsof the screen surface brightness whereby enabling the infrared light tobe easily recorded on an imaging means of a person conducting anunauthorized act. The description of (6a) also applies to this system.

For example, electronic circuits such as a computer or an IC forspecific purpose may be employed as the infrared light projectioncontrol unit. More specifically, it requires memory means for recordinga predetermined value, comparison means for comparing the predeterminedvalue and the detection value, means for specifically controlling theemission of the infrared light projector means based on the comparisonresult.

In case that a plural of the comparison results are considered,corresponding functional means is required. For example, it furtherrequires means for counting the number of light sensors in which thebrightness equal or less than the predetermined number is detected,memory means for recording a predetermined number that becomes acomparison reference number, comparison means for comparing thesepredetermined numbers and actual measurement values (counting values)and so on when the infrared light projector means emit only in case thatthe number of areas in which the brightness is less than thepredetermined value is equal or bigger than a predetermined number insingle scene or a region to be detected.

Further, in case that, for example, emissions of the infrared lightprojector means are switched in accordance with a distribution patternof the areas in which the brightness is less than the predeterminedvalue over the screen, it further requires memory means for recordingdistribution patterns to be considered, determination means fordetermining which of the distribution patterns is matched to themeasured pattern by comparing with the stored distribution patterns,means for specifying the infrared light projector means to beemission-controlled based on the determined distribution pattern, and soon. Of course, these functions may be realized by means of software orhardware.

(14b) System utilizing an infrared light projection control unit forindividually controlling at least one or more infrared light projectormeans to project infrared light from the infrared light projector meansassociated with an area corresponding to the light sensor from which thedetection result is obtained in case that a brightness of the screensurface is equal or less than a predetermined brightness, instead ofusing the infrared light projection control unit of (14a):

This system corresponds to the above-cited method (6b). That is, thissystem enables to adaptively project the infrared light onto partialareas of the screen surface having the low brightness whereby enablingthe infrared light image to be easily recorded not for whole area of thescreen but for partial areas. The description of (6b) also applies tothis system.

(14c) System utilizing reproducing means for reproducing timeinformation in which brightness at the screen becomes equal or less thana predetermined brightness value from a recording medium, and aninfrared light projection control unit for controlling projection ofinfrared light from the at least one or more infrared light projectormeans in accordance with the reproduced information, instead of usingthe light sensor and the infrared light projection control unit of(14a):

This system corresponds to the above-cited method (6c). That is, thissystem assumes a case in which the time periods of low brightness arestored as information in the recording medium and not determined by themeasurement results. The system does not require the light sensor. Thedescription of (6c) also applies to this system.

(14d) System utilizing reproducing means for reproducing area and timeinformation in which brightness at the screen becomes equal or less thana predetermined brightness value from a recording medium, and aninfrared light projection control unit for individually controllingprojection of infrared light from the at least one or more infraredlight projector means associated with corresponding areas of the screenin accordance with the reproduced information, instead of using thelight sensor and the infrared light projection control unit of (14a):

This system corresponds to the above-cited method (6d). That is, thissystem assumes a case in which the partial areas and the time periods oflow brightness are stored as information in the recording medium and notdetermined by the measurement results. The system does not require thelight sensor. The description of (6d) also applies to this system.

(14e) System utilizing receiving means for receiving information from anetwork for time in which brightness at the screen becomes equal or lessthan a predetermined brightness value in synchronization with theprojection of said visual image, and an infrared light projectioncontrol unit for controlling projection of infrared light from the atleast one or more infrared light projector means in accordance with thereceived information, instead of using the light sensor and the infraredlight projection control unit of (14a):

This system corresponds to the above-cited method (6e). That is, thissystem assumes a case in which the time periods of low brightness arereceived via the network and not determined by the measurement results.The system does not require the light sensor nor brightness detectionmeans. The description of (6e) also applies to this system.

(14f) System utilizing receiving means for receiving information from anetwork for area and time in which brightness at the screen becomesequal or less than a predetermined brightness value in synchronizationwith the projection of visual image, and an infrared light projectioncontrol unit for individually controlling projection of infrared lightfrom the at least one or more infrared light projector means associatedwith corresponding areas on the screen in accordance with the receivedinformation, instead of using the light sensor and the infrared lightprojection control unit of (14a):

This system corresponds to the above-cited method (6f). That is, thissystem assumes a case in which the partial areas and the time periods oflow brightness are received via the network and not determined by themeasurement results. The system does not require to dispose the lightsensor. The description of (6f) also applies to this system.

(14g) System utilizing shielding period detection means for detecting aperiod of shielding the projection light with a frame transferringshutter, and an infrared light projection control unit for controllingemission of the infrared light projector means based on detectionresults of the shielding period detection means, instead of using thelight sensor and the infrared light projection control unit of (14a):

This system corresponds to the above-cited method (6g). That is, thissystem ensures the recording of the infrared light image by projectingthe infrared light with consideration of a decrease in the screensurface brightness during a period of the frame transferring shutterclosing. The description of (6f) also applies to this system.

As the shielding period detection means, following methods may becontemplated. The method may be a method for mechanically detecting thefilm transfer, or a method for electronically detecting the filmtransfer using a change of electrostatic capacitance or the like, or amethod for mechanically detecting a motion of the shutter mechanism, ora method for electronically detecting a motion of the shutter mechanism.

(15) As an imaging prevention system for interfering unauthorizedimaging of visual image projected on a screen, the following isprovided. The system is to dispose at least one or more infrared lightprojector means in a vicinity of the screen surface at a front side ofthe screen viewing from viewers/audiences so as the infrared lightreflected on the screen incident into an imaging means of a personconducting the unauthorized act.

This system corresponds to the above-cited method (7). That is, thissystem enables an ample amount of the reflected infrared light incidentinto the imaging means of a person conducting the unauthorized act byprojecting the infrared light to the screen from locations at thevicinity of the screen. The description of (7) also applies to thissystem.

(16) As an imaging prevention system for interfering unauthorizedimaging of visual image projected on a screen, the following isprovided. The system comprises at least one or more infrared lightprojector means disposed in a vicinity of the screen surface forprojecting infrared light to the screen, projecting direction actuatormeans for driving the infrared light projector means to vary itsprojecting direction, memory means for recording projecting directioninformation of each infrared light projector means according to a screensize, and projecting direction control means for reading out theprojecting direction information from the memory means when aninstruction to change the screen size is detected, for providing theread-out information to said projecting direction actuator means, andfor automatically adjusting a projecting direction of said infraredlight projector means.

This system corresponds to the above-cited method (8). That is, thissystem enables to provide the optimum projecting direction according tothe screen size (aspect ratio) by automatically adjusting the projectingdirection of the infrared light in conjunction with the change of thescreen size. The description of (7) also applies to this system.

The system is suitable for a projection system having a plural screensizes each suited for the visual image projection and required to changethe screen size when necessary. For example, in a commercial system suchas a movie theater, the screen size (aspect ratio) may be Standard(1:1.33), Europe Vista (1:1.66), America Vista (1:1.85), Scope (1:2.35),and so on. These values are examples of some typical values, and notlimited only to these values.

The projecting direction information stored in the memory means may be,for example, a horizontal angle, an elevation angle, or the otherinformation. Of course, an amount of motion or the other control valuesmay be used instead of the angle. The projecting direction actuatormeans may comprise, for example, means for turning around an axis towhich the infrared light projection means is attached, means forrotating or horizontally transporting a base on which the infrared lightprojection means is fixed, or the other means. As the projectingdirection control means, a computer, an IC for specific purpose or theother electronic circuits may be used, for example.

(B) Specific Embodiment

In the following, the specific embodiments of imaging prevention methodand system in accordance with the present invention will now bedescribed.

(1) First Embodiment Example

The first embodiment example is shown in FIG. 1. This embodiment exampleis related to a novel feature of projecting infrared light to aviewer/audience direction from a rear side of the screen. FIG. 1 showsan example applicable for a movie theater or other theater systems. Ofcourse, the technique itself may be applicable to a home theater. In anycases, the visual images projected onto the screen include televisionprograms and the other copyrighted products as well as a movie. Next, aspecific example of each apparatus composing the system shown in FIG. 1will now be described.

A projector apparatus 1 is a projection apparatus projecting visualimages to be viewed/listened onto a screen 2. The projector apparatus 1may be, for example, a film projector for projecting a movie film, aslide projector for projecting a slide, an overhead projector (OHP), aliquid crystal projector for directly projecting a digital image, adigital micro-mirror device (DMD) projector, a CRT projector or thelike.

Although, FIG. 1 shows a type in which the projector apparatus 1 isdisposed at a rear side of audience seats 4 and the reflected light atthe screen surface is viewed by viewers/audiences, a location of theprojector apparatus 1 is not limited to this particular one. Forexample, it is possible to contemplate that the projector apparatus 1may be disposed a front side of the audience seats 4 (namely, betweenthe screen 2 and the audience seats 4), or at above of the audienceseats 4, or at a side wall side. Of course, the projector apparatus 1may be disposed in a rear side of the screen 2 in case that visualimages are projected from the rear side of the screen and itstransmission light is viewed by the viewers/audiences (so-called a rearprojection type).

The screen 2 shown in FIG. 1 is a theater screen. In general, soundsource holes (ventilation holes or any other structures connecting therear side and the front side) called as a sound perforation are formedso as to effectively propagate sound from the sound source disposed atthe rear side of the screen to the viewers/audiences side. An arbitraryshape or size or position may be selected for the sound perforation.FIG. 2 shows an example of the sound perforation. In the presentspecification, the sound perforation is used to transmit infrared lightfrom the rear side of the screen to the front side.

The screen 2 of FIG. 1 may be a screen without the sound perforation. Insuch case, it is preferred to have characteristics of having a screencomprising a material capable of transmitting the infrared light easily,or a screen with embedded members capable of transmitting the infraredlight easily, or a screen having parts of thinner thickness than therest of the screen.

An infrared light projector apparatus 3 is a projector apparatusprojecting an infrared light to prevent unauthorized imaging of visualimages projected onto the screen. It utilizes features of that theinfrared light is not recognized by the viewers/audiences while sensedby CCD (solid state imaging device) of an imaging apparatus. It ispossible to contemplate that the infrared light projector apparatus 3may be, for example, a light emitting diode or any other devicesemitting light flux mainly comprising of the infrared light, or a deviceof type in which an infrared light transmission filter is disposed at alight path and only the infrared light is finally outputted, or a deviceof type in which a visible light cut-filter and/or an ultra-violetcut-filter are disposed at a light path and only the infrared light isfinally outputted.

It is considered that a typical location of the infrared light projectorapparatus 3 is at a vicinity of the rear side of the screen. Theposition may be set an arbitrary location provided that the infraredlight projector apparatus 3 is disposed at the rear side of a virtualreference plane including the screen surface viewing from the audienceseats 4. For example, the infrared light projector apparatus 3 may bedisposed at obliquely rear side of the screen (outside of the screen 2frame) whereby a part or all of the infrared light may pass throughspace outside of the screen and be projected to the audience seats 4.The infrared light projector apparatus 3 may be embedded in the screenitself.

The infrared light projector apparatus 3 may be disposed in anyarbitrary height provided that it is disposed at the rear space of thescreen. The infrared light projector apparatus 3 may be positioned in avicinity of the lower section of the screen 2 (height of the infraredlight projector apparatus 3 may be higher or lower than the bottom hemof the screen 2) or in a vicinity of the middle section of the screen 2,or in a vicinity of the upper section of the screen 2 (height of theinfrared light projector apparatus 3 may be higher or lower than the tophem of the screen 2). The optimum height of the infrared light projectorapparatus 3 may vary depending on a relationship of the audience seats 4and the screen 2. In general, the infrared light projector apparatus 3may be disposed within an imaging area (or imaging angle) of the imagingapparatus used for the unauthorized imaging.

The projecting direction of the infrared light may be set arbitraryprovided that the projected light flux is directed to an area or spaceat where the unauthorized imaging may take place. At least, thefollowing directions may be selected. The directions is such that theprojected light flux can cover a region with a certain height where theimaging without any interference is possible within the area in whichthe audience seats 4 are disposed. For example, in case that theinfrared light projector apparatus 3 are disposed at vicinities of bothright and left side edges of the screen 2 as shown in FIG. 3, theinfrared light may be projected to obliquely front directions from theirlocations. Further, in case that the infrared light projector apparatus3 is disposed at a vicinity of the top section of the screen 2, theprojecting direction of the infrared light becomes an obliquely downwarddirection. In order to increase the prevention effect, it is preferableto arrange a light axis of the optical system in the imaging apparatusused for the unauthorized act and a light axis of the infrared light insuch a way that both light axes become as parallel as possible.

Alternatively, in case that the light axis of the infrared light ischanged by utilizing the infrared light reflection mirror (so-called hotmirror) or any other infrared light reflection unit, the light axis ofthe reflected infrared light may be needed to be directed to theabove-mentioned region or space. Instead of reflecting the infraredlight by the reflection mirror as mentioned in the above, the projectionlight axis of the reflected infrared light may be directed to theabove-mentioned region or space by driving the infrared light projectorapparatus 3 itself. For example, the infrared light projector apparatus3 may be driven in a horizontal direction so as that the reflected lightscans the audience side.

In any of the above-cited cases, it is preferable to determinedisposition (location and height) of the infrared light projectorapparatus or projecting direction so as to reduce an angle differencebetween the optical axis of the imaging apparatus and the light axis ofthe infrared light as much as possible. This is because the infraredlight becomes easier to be recorded and the prevention effect becomeslarger when the angle difference between the optical axis of the imagingapparatus and the light axis of the infrared light is smaller. The samethings applies to the other embodiments.

Further, the infrared light may be a spread light having spread lightflux, or a spot light having a tightened light flux. Alternatively, theinfrared light may be projected to focus on the screen so as that apredetermined information (for example, output date/time, outputlocation, screen number, output apparatus, output performer, or anyother information required to identify a location in which theunauthorized act is performed) or character information (include marksand any other identifiable graphic information) may be recorded.Although it is a typical to use a constant emission (light on) for theinfrared light providing these information, it is possible to provide apredetermined information by a technique of intermittently emitting theinfrared light.

In addition to the above, the infrared light projection method mayinclude a method for emitting the infrared light intermittently. Byintermittently projecting the infrared light, the viewing becomesdifficult since the brightness of the recorded screen variesindependently with respect to visual images of the main feature of aprogram. It is also possible to enable reading out of desiredinformation from appearance timings or appearance locations of therecorded light images by controlling the timing of the intermittentemission or the emission location of the infrared light projectorapparatus 3. Any arbitrary intermittent emission methods described abovemay be utilized. Concrete emission methods will be described with theother embodiments in the following.

The number of the infrared light projector apparatus 3 is not limited toone. For example, FIG. 1 or FIG. 3 show cases where two of the infraredlight projector apparatus 3 are used. Of course, three or more of theinfrared light projector apparatus 3 may be disposed at discretion. FIG.1 or FIG. 3 seems to show the infrared light projector apparatus 3 withsingle infrared light emission device. However, a plurality of theinfrared light emission devices may also be mounted on the singleinfrared light projector apparatus 3. In this case, a simultaneousemission control of all the infrared light emission devices or anindividual emission control may be performed at discretion.

The amount of the infrared light entering the imaging apparatus may beincreased by projecting the infrared light to the audience seats fromthe rear side of the screen 2 as the present embodiment, morespecifically by disposing the imaging apparatus for imaging visualimages projected on the screen in the unauthorized manner and theinfrared light projector apparatus 3 for projecting the infrared lightto prevent such unauthorized imaging in a face-to-face position and byprojecting the infrared light to directly incident into the imagingapparatus from the infrared light projector apparatus 3.

Consequently, the prevention effect greater than that of a conventionalsystem may be expected. Further, the infrared light projector apparatus3 having a emission brightness (output) less than the conventionalsystem may be used when only the comparable prevention effect isrequired. Accordingly, an economical effect may be promoted in theapparatus or its system.

In case that the infrared light transmits through the screen, theprevention effect greater than a conventional system may be realized byutilizing a screen allowing easy transmission of the infrared light (forexample, by utilizing a screen having material itself transmits easily,or a screen in which members having a high transmittance for theinfrared light are partially embedded, or a screen in which concavedportions are partially formed for easy transmission of the infraredlight). Particularly, in case that the screen capable of easytransmission of the infrared light is used, the present embodimentexample has a far greater merit since ample amount of the reflectedlight may not be anticipated for application of the conventional system.For example, in case that a rear projection type projector apparatus isincluded in the system, desired effect may not be obtained even when theconventional system is applied.

As described above, the system according to the present embodiment canachieve the prevention effect greater than the conventional systemregardless of the infrared light paths to the front area or space of thescreen.

(2) Second Embodiment Example

The second embodiment example is shown in FIG. 4. This embodimentexample is related to a novel feature of projecting infrared light to aviewer/audience direction from a front side of the screen. FIG. 4 alsoshows an example applicable for a movie theater or other theatersystems. Similar to the first embodiment example, the technique itselfmay be applicable to a home theater. Of course, the visual imagesprojected onto the screen include television programs and the othercopyrighted products as well as a movie. Next, a specific example ofeach apparatus composing the system shown in FIG. 4 will now bedescribed. Here, an explanation of the projector apparatus 1 is omittedsince it is similar to the first embodiment example.

Contrary to the first embodiment example, the screen 2 may have anyarbitrary construction. That is, the screen of FIG. 4 may be a screenhaving a configuration capable of easily transmitting the infraredlight, or a screen having a configuration capable of transmitting theinfrared light, or a screen incapable of transmitting nor passingthrough the infrared light. This is because that the infrared lightprojector apparatus 3 is disposed in the front of the screen 2 and anexistence of the screen does not interfere the incident of the infraredlight into the imaging apparatus.

An apparatus construction itself of the infrared light projectorapparatus 3 is the same as that of the first embodiment example.Differences are a location and a projection method of the infrared lightprojector apparatus 3 and so on. It is considered that a typicallocation of the infrared light projector apparatus 3 is at a vicinity ofthe both sides of the screen so as not to interfere the viewing of themain feature program. However, the position may be set an arbitrarylocation provided that the infrared light projector apparatus 3 isdisposed at an audience seat side from the virtual reference planeincluding the screen surface.

For example, it may be disposed at a vicinity of the center of thescreen's bottom hem below an area onto which the visual images areprojected. Similarly, it may be disposed at a vicinity of the center ofthe screen's top hem above an area onto which the visual images areprojected. Alternatively, it may be disposed at a side wall part in theaudience seat side from the virtual reference plane including the screensurface. For the theater system such as a movie theater, it may beembedded in such a way that the infrared light can be projected to theopposite side of the screen at above the seat's backrest portion. Incase that such construction is utilized, a great prevention effect maybe anticipated since the infrared light may be projected from a closerange to the imaging apparatus even when the infrared light projectorapparatus 3 with rather low output is used. Alternatively, the infraredlight projector apparatus 3 may be disposed at a ceiling above theaudience seat. It is preferred to mount the infrared light projectorapparatus 3 on a surface (audience side plane) of the screen 2 if itdoes not interfere the viewing.

Further, similar to the first embodiment example, a disposition heightof the infrared light projector apparatus 3 is not limited to anyparticular value. The optimum height of the infrared light projectorapparatus 3 may vary depending on a relationship of the audience seats 4and the screen 2. In general, the infrared light projector apparatus 3may be disposed within an imaging area (or imaging angle) of the imagingapparatus used for the unauthorized imaging.

Similarly, the projecting direction of the infrared light may bearbitrary determined provided that the projected light flux is directedto an area or space at where the unauthorized imaging may take place. Atleast, the following directions may be selected. The directions is suchthat the projected light flux can cover a region with a certain heightwhere the imaging without any interference is possible within the areain which the audience seats 4 are disposed. Alternatively, in case thatthe light axis of the infrared light is changed by utilizing theinfrared light reflection mirror (so-called hot mirror) or any otherinfrared light reflection unit, the light axis of the reflected infraredlight may be needed to be directed to the above-mentioned region orspace. Instead of reflecting the infrared light by the reflection mirroras mentioned the above, the light axis of the reflected infrared lightmay be directed to the above-mentioned region or space by driving theinfrared light projector apparatus 3 itself. For example, the infraredlight projector apparatus 3 may be driven in a horizontal direction soas that the reflected light scans the audience side.

Also in the above-cited cases, it is preferable to determine disposition(location and height) of the infrared light projector apparatus orprojecting direction so as to reduce an angle difference between theoptical axis of the imaging apparatus and the light axis of the infraredlight as much as possible. This is because the infrared light becomeseasier to be recorded and the prevention effect becomes larger when theangle difference between the optical axis of the imaging apparatus andthe light axis of the infrared light is smaller.

Further, the infrared light may be a spread light having spread lightflux, or a spot light having a tightened light flux. The infrared lightmay be a constantly emitted (light on) or an intermittently emitted. Byintermittently projecting the infrared light, the viewing becomesdifficult since the brightness of the recorded screen variesindependently with respect to visual images of the main feature of aprogram. Intervals of the intermittent emission may be varied at random.By changing the emission interval randomly, it is possible to preventelimination of the brightness changes from the visual images imaged bythe unauthorized manner even with using image processing.

It is also possible to enable reading out of desired information fromappearance timings or appearance locations of the light images bycontrolling the timing of the intermittent emission, or by controllingemission positions of the infrared light projector apparatus 3 when aplurality of the infrared light projector apparatus 3 are used. Anyarbitrary intermittent emission methods described above may be utilized.Concrete emission methods will be described with the other embodimentsin the following.

Also in this embodiment example, the number of the infrared lightprojector apparatus 3 is not limited to one. For example, FIG. 4 showcases where two of the infrared light projector apparatus 3 are used. Ofcourse, three or more of the infrared light projector apparatus 3 oronly one of the infrared light projector apparatus 3 may be disposed.FIG. 4 seems to show the infrared light projector apparatus 3 withsingle infrared light emission device. However, a plurality of theinfrared light emission devices may also be mounted on the singleinfrared light projector apparatus 3. In this case, a simultaneousemission control of all the infrared light emission devices or anindividual emission control may be performed at discretion.

The amount of the infrared light entering the imaging apparatus may beincreased more than the first embodiment example by projecting theinfrared light to the audience seats from the front side of the screen 2as the present embodiment, more specifically by disposing the imagingapparatus for imaging visual images projected on the screen in theunauthorized manner and the infrared light projector apparatus 3 forprojecting the infrared light to prevent such unauthorized imaging in aface-to-face position and by projecting the infrared light to directlyincident into the imaging apparatus from the infrared light projectorapparatus 3 at closer range than the first embodiment example.

Consequently, the prevention effect greater than that of a conventionalsystem may be expected. Further, the infrared light projector apparatus3 having a emission brightness (output) less than the conventionalsystem may be used when only the prevention effect comparable to that ofthe conventional system is required. Accordingly, an economical effectmay be promoted in the apparatus or its system.

In case that the infrared light transmits through the screen, theprevention effect greater than a conventional system may be realizedsince no reflection at the screen surface is required in the presentembodiment while only the less than the adequate amount of thereflection light is anticipated in the conventional system technique.For example, in case that a rear projection type projector apparatus isincluded in the system, desired effect may not be obtained even when theconventional system is applied.

As described above, the system according to the present embodiment canachieve the prevention effect greater than the conventional systemregardless of the infrared light paths to the front area or space of thescreen.

(3) Third Embodiment Example

The third embodiment example is shown in FIG. 5 and FIG. 6. Thisembodiment example is related to a novel feature of projecting infraredlight to a viewer/audience direction from a side of the screen. FIG. 5show an example of case in which the infrared light projector apparatus3 is disposed outside (above) the top hem of the screen 2. FIG. 6 showan example of case in which the infrared light projector apparatus 3 aredisposed outside (above) the top hem of the screen 2 and outsides ofboth left and right sides. All of figures shows application examples forthe movie theater or any other theater system.

Similar to the first embodiment example, the technique itself may beapplicable to a home theater. Of course, the visual images projectedonto the screen include television programs and the other copyrightedproducts as well as a movie. Next, a specific example of each apparatuscomposing the system shown in FIG. 5 and FIG. 6 will now be described.Here, an explanation of the projector apparatus 1 is omitted since it issimilar to the first embodiment example.

The screen 2 with the same construction as the second embodiment exampleis used. That is, the screen may be a screen having a configurationcapable of easily transmitting the infrared light, or a screen having aconfiguration allowing infrared light pass-through, or a screenincapable of transmitting nor passing through the infrared light. Thisis because that the infrared light projector apparatus 3 is disposedaround the screen 2 and an existence of the screen does not interferethe incident of the infrared light into the imaging apparatus.

An apparatus construction itself of the infrared light projectorapparatus 3 is the same as that of the first embodiment example.Differences are a location and a projection method of the infrared lightprojector apparatus 3 and so on. It is considered that a typicallocation of the infrared light projector apparatus 3 is in a vicinity ofthe outer peripheral of the screen. Because the closer to an area towhich the main feature program is projected, it is easier for theprojected infrared light to be recorded in a typical case (inside theimaging area to be directly recorded, or higher probability to affectthe imaging area) whereby promote the prevention effect. The preventioneffect may not be necessary to be decreased even at space outside thescreen outer peripheral since the probability of the infrared lightrecording is relative one determined by a relationship with an imagingangle of the imaging apparatus.

For example, as shown in FIG. 5, the infrared light may be easilyprojected over a wide range of area when two of the infrared lightprojector apparatus 3 are disposed in such a way that the infrared lightprojector apparatus 3 are contacting on the screen's top hem. Foranother example, as shown in FIG. 6, dead angles of the preventableareas, caused by mismatching of the light axes of the projected infraredlights and the optical system axis of the imaging apparatus, may becovered when a plurality of the infrared light projector apparatus 3 aredisposed in such a way that the infrared light projector apparatus 3 arecontacting on the screen's top hem and single infrared light projectorapparatus 3 is disposed in both sides (light and left) of the screen.For an example of FIG. 6, the infrared light projected from the top partof the screen may not incident into the imaging apparatus positioned inthe back side of the audience seats (particularly in FIG. 6, slanting ofthe audience seat floor may also be one of the causes). However, theample amount of the infrared light may be directly projected to theaudience seats located in the back side by projecting the infrared lightfrom the both sides (right and left) whereby eliminating the dead anglesof the preventable areas in the system as a whole. In order to produceno dead angle in the audience seats in the top front row, it iseffective to dispose the infrared light projector apparatus at outsidethe screen's bottom hem or to combine with the first embodiment exampletechnique, namely the technique in which the infrared light is projectedfrom the rear side of the screen.

Further, similar to the first embodiment example or the secondembodiment example, a disposition height of the infrared light projectorapparatus 3 is not limited to any particular value. The optimum heightof the infrared light projector apparatus 3 may vary depending on arelationship of the audience seats 4 and the screen 2.

Similarly, the projecting direction of the infrared light may bearbitrary determined provided that the projected light flux is directedto an area or space at where the unauthorized imaging may take place. Atleast, the following directions may be selected. The directions is suchthat the projected light flux can cover a region with a certain heightwhere the imaging without any interference is possible within the areain which the audience seats 4 are disposed. Alternatively, in case thatthe light axis of the infrared light is changed by utilizing theinfrared light reflection mirror (so-called hot mirror) or any otherinfrared light reflection unit, the light axis of the reflected infraredlight may be needed to be directed to the above-mentioned region orspace. Instead of reflecting the infrared light by the reflecting mirroras mentioned the above, the light axis of the reflected infrared lightmay be directed to the above-mentioned region or space by driving theinfrared light projector apparatus 3 itself. For example, the infraredlight projector apparatus 3 may be driven in a horizontal direction soas that the reflected light scans the audience side.

Also in the above-cited case, it is preferable to determine disposition(location and height) of the infrared light projector apparatus orprojecting direction so as to reduce an angle difference between theoptical axis of the imaging apparatus and the light axis of the infraredlight as much as possible. This is because the infrared light becomeseasier to be recorded and the prevention effect becomes larger when theangle difference between the optical axis of the imaging apparatus andthe light axis of the infrared light is smaller.

Further, the infrared light may be a spread light having spread lightflux, or a spot light having a tightened light flux. The infrared lightmay be a constantly emitted (light on) or an intermittently emitted. Byintermittently projecting the infrared light, the viewing becomesdifficult since the brightness of the recorded screen variesindependently with respect to visual images of the main feature of aprogram. It is also possible to enable reading out of desiredinformation from appearance timings or appearance locations of therecorded light images by controlling the timing of the intermittentemission, or by controlling emission positions when a plurality of theinfrared light projector apparatus 3 are used. Any arbitraryintermittent emission methods described above may be utilized. Concreteemission methods will be described with the other embodiments in thefollowing.

Also in this embodiment example, the number of the infrared lightprojector apparatus 3 is not limited to one. For example, FIG. 5 showcases where two of the infrared light projector apparatus 3 are used. Ofcourse, three or more of the infrared light projector apparatus 3 oronly one of the infrared light projector apparatus 3 may be disposed.FIG. 5 seems to show the infrared light projector apparatus 3 withsingle infrared light emission device. However, a plurality of theinfrared light emission devices may also be mounted on the singleinfrared light projector apparatus 3. In this case, a simultaneousemission control of all the infrared light emission devices or anindividual emission control may be performed at discretion.

The amount of the infrared light entering the imaging apparatus may beincreased more than the first embodiment example by projecting theinfrared light to the audience seats from the vicinity of the screen 2as the present embodiment, more specifically by disposing the imagingapparatus for imaging visual images projected on the screen in theunauthorized manner and the infrared light projector apparatus 3 forprojecting the infrared light to prevent such unauthorized imaging in aface-to-face position and by projecting the infrared light to directlyincident into the imaging apparatus from the infrared light projectorapparatus 3 at closer range than the first embodiment example.

Consequently, the prevention effect greater than that of a conventionalsystem may be expected. Further, the infrared light projector apparatus3 having a emission brightness (output) less than the conventionalsystem may be used when only the prevention effect comparable to that ofthe conventional system is required. Accordingly, an economical effectmay be promoted in the apparatus or its system.

In case that the infrared light transmits through the screen, theprevention effect greater than a conventional system may be realizedsince no reflection at the screen surface is required in the presentembodiment while only the less than the adequate amount of thereflection light is anticipated in the conventional system technique.For example, in case that a rear projection type projector apparatus isincluded in the system, desired effect may not be obtained even when theconventional system is applied.

As described above, the system according to the present embodiment canachieve the prevention effect greater than the conventional systemregardless of the infrared light paths to the front area or space of thescreen.

(4) Fourth Embodiment Example

The fourth embodiment example is shown in FIG. 7. This embodimentexample is related to a novel feature of projecting infrared light to ainfrared light reflection mirror 5 having a high reflection ratio andfor enabling the reflected light incident into the imaging apparatus ofa person conducting the unauthorized act. In a system shown in FIG. 7, areflection direction itself may be variable by driving the infraredlight reflection mirror 5 with an actuator apparatus 6.

FIG. 7 shows an application example of a movie theater or any othertheater systems. Similar to the first embodiment example, the techniqueitself may also be applicable to a home theater. Of course, the visualimages projected onto the screen include television programs and theother copyrighted products as well as a movie. Next, a specific exampleof each apparatus composing the system shown in FIG. 7 will now bedescribed. Here, an explanation of the projector apparatus 1 is omittedsince it is similar to the first embodiment example.

The screen 2 may be different depending at where the infrared lightreflection mirror 5 is disposed. In the example of FIG. 7, the infraredlight reflection mirror 5 is disposed in a vicinity of the screen 2.Accordingly, the same construction may be applied as the thirdembodiment example when the reflection surface is identified as theprojection source of the infrared light. In this case, any arbitrarymaterials or constructions may be used as the screen of the thirdembodiment example. The same applies to a case of disposing the infraredlight reflection mirror 5 in the front of the screen 2.

In case that the infrared light reflection mirror 5 is disposed in therear side of the screen so as that the reflected light is projected tothe audience seat side via passing or transmitting through the screen 2,the particular construction or material should be used as the screen ofthe first embodiment example. Alternatively, any arbitrary constructionsmay be applied to the screen 2 as the second embodiment example and thethird embodiment example even in case that the infrared light reflectionmirror 5 is disposed in the rear side of the screen provided that thereflected light passes through space outside of the screen.

An apparatus construction itself of the infrared light projectorapparatus 3 is the same as that of the first embodiment example.Differences are a location and a projection method of the infrared lightprojector apparatus 3 and so on. A disposition location of the infraredlight projector apparatus 3 may be determined by a relationship with thereflection surface of the infrared light reflection mirror 5.

For example, the infrared light projector apparatus 3 is disposed closerto the audience seat side than the infrared light reflection mirror 5whatever the physical relationship of the infrared light reflectionmirror 5 and the screen 2 may be provided that the reflection surface ofthe infrared light reflection mirror 5 is positioned parallel orsubstantially parallel to the screen 2 as shown in FIG. 7. Of course,this is to direct the reflected light to the audience seat direction.

On the other hand, the infrared light projector apparatus 3 is disposedthe back side of the infrared light reflection mirror 5 (viewing fromthe audience seat side to the screen direction) whatever the physicalrelationship of the infrared light reflection mirror 5 and the screen 2may be provided that the reflection surface of the infrared lightreflection mirror 5 is positioned perpendicular or substantiallyperpendicular to the screen 2. In this case, an incident angle (anglewith respect to the normal direction of the reflection surface) of theinfrared light typically becomes larger with respect to the reflectionsurface.

In any of the above cited cases, the infrared light is projected fromthe infrared light projector apparatus 3 so as that the infrared lightreflected shines over at least a part of areas or regions in which theunauthorized act may be performed. The positional relationship of thereflection surface and the screen is not limited to the above cases, andthe positional relationship falls in somewhere in the middle of theabove cases may also be utilized. Of course, the optimum position or theoptimum projection direction of the infrared light projection apparatus3 may be different depending on the physical relationship with thereflection surface of the infrared light reflection mirror 5.

In an example of FIG. 7, the reflection direction of the infrared lightmay be configured as variable even that the projecting direction of theinfrared light projector apparatus 3 is fixed since the infrared lightreflection mirror 5 (reflection surface) may be driven with the actuatorapparatus 6 whereby producing no dead angle in the imaging preventablearea.

The infrared light reflection mirror 5 (reflection surface) isconfigured as movable in this embodiment example, no dead angle may beproduced in the imaging preventable area even in case that the infraredlight reflection mirror 5 (reflection surface) is fixed (namely, noactuator apparatus 6 is not included in the configuration) by disposinga plurality of the infrared light projector apparatus 3 in variouspositions and reflecting the infrared lights projected from each of theinfrared light projector apparatus 3. Alternatively, the reflectiondirection may be configured as variable by driving the infrared lightprojector apparatus 3 with the actuator apparatus 6 and reflecting bythe infrared light reflection mirror 5.

The infrared light reflection mirror 5 is a mirror with a high infraredlight reflection ratio. A high reflection ratio may be preferred notonly for the infrared light but also for light in the other frequencyband. Of course, it is preferable to have low reflection ratio forvisible light. In case that the infrared light reflection mirror 5 isdisposed at a location at which there is no possibility of entering thevisible light, the high reflection ratio for the visible light may causeno trouble.

The infrared light reflection mirror 5 may have a plate-type shape or ashape like a concave or a convex mirror. In case that the convex mirroris used, there is a merit of reflecting the infrared light in a widearea even when the projecting direction of the infrared light is fixedor a movable range of the infrared light reflection mirror 5 is limited(including a case of being fixed). In this case, a spread light flux maybe used for the infrared light to be projected.

The infrared light reflection mirror 5 may be a one-sided mirror havingsingle reflection surface only at one side, or two-sided mirror havingreflection mirrors in both sides. The infrared light reflection mirror 5may be constructed from single mirror or constructed as assembled bodycomprising a plurality of mirrors. For example, it may be constructed byarraying a plurality of micro mirrors on a plane. Alternatively, it maybe constructed by arraying a plurality of micro mirrors so as to form apolyhedron body (including a sphere) as a whole.

When the infrared light reflection mirror 5 has the polyhedron form, itis possible to be used for reflecting single light flux into a pluralityof directions even the infrared light reflection mirror 5 is fixed. Ofcourse, in case that the polyhedron form is employed and moved, thereflection light may be reflected to a wide area by largely changingangles of the reflection surfaces with a small amount of the movement.

Although the infrared light reflection mirror 5 is utilized in FIG. 7,the reflection surface is not necessary to have a mirror surfaceprovided that it can reflect the infrared light with a high reflectionratio. That is, means for reflecting the infrared light may include notonly the infrared light reflection apparatus but also a scattering plateor the like.

Further, only one infrared light reflection mirror 5 is disposed at avicinity of the center of the screen's top hem in FIG. 7. However, thedisposition and the number of the infrared light reflection mirror 5 arenot limited to those of FIG. 7. For example, it may be disposed in avicinity of the center of the screen's bottom hem, or in vicinities ofboth sides (right and left hem) of the screen. Of course, it is notlimited to the center vicinity of each hem but may be disposed in anypositions. Further, it may disposed not only at the vicinity of thescreen but disposed by a side wall or ceiling, or the front or rear sideof the screen, or any other various positions. Of course, the number isnot limited to one but the infrared light reflection mirror 5 may bedisposed in a plurality of positions.

The actuator apparatus 6 is means for changing the reflection directionof the infrared light by driving the infrared light reflection mirror 5or its reflection surface. FIG. 8 shows an example of the actuatorapparatus. The apparatus shown in FIG. 8 has a motor 6A and a rotationaxis 6B as principle units. In case of FIG. 8, the infrared lightreflection mirror 5 mounted on the rotation axis 6B is rotationallydriven to one direction (360 degree) by the motor 6A. That is, itbecomes possible to horizontally scan the audience seat side with theinfrared light by changing the angle of the reflection surface (theinfrared light reflection mirror 5 itself in case of FIG. 8).

An appropriate value of the rotation angle or the rotation speed isselectively used in accordance with effects to be achieved. For example,the following drive method may be used. The method is to drive theinfrared light reflection mirror 5 in reciprocating manner within theminimum range (for example 90 degree) required for scanning the audienceseats with the reflected light. The driving speed may be a low speedsuch that single infrared light scanning is completed within a period ofplural frames to a high speed such that plural infrared light scanningare performed within a period of single frame. A difference of thedriving speed relates to a frequency of the light image appearance inthe visual images imaged in the unauthorized manner.

In case of the actuator apparatus of FIG. 8, it is shown a case that thedrive axis of the actuator apparatus 5 is a single-axis. However, it isalso applicable to a case in which the drive axis is a two-axis ofdifferent directions such as horizontal and vertical directions. Withincreasing the drive axis having a different axis direction, it ispossible to expand the area to be covered by the scanning with theinfrared light. Of course, the drive axis is not limited to thetwo-axis, and may be the three-axis or more. Although the most simpleactuator mechanism in which the infrared light reflection mirror 5 isfixed on the rotation axis 6B of the motor 6A is shown in FIG. 8, a gearor any other mechanisms, or, a rubber or any other elastic members maybe utilized as means for transmitting power of the motor 6A. Further, itis possible to contemplate that the power source may be ones using arotational direction like the motor 6A, or ones using a linear directionlike a linear motor, or ones utilizing elastic waves like a elastic wavemotor, or ones utilizing an electromagnet, or the like. For example, theinfrared light reflection mirror 5 may be moved horizontally along a hemof the screen 2 whereby moving the area illuminating the reflectedinfrared light.

FIG. 8 shows an example of the actuator apparatus in case that theinfrared light reflection mirror 5 is formed with single mirror.However, in case that the infrared light reflection mirror 5 is formedfrom a plurality of mirrors as means for reflecting the infrared light,it is possible to provide actuator apparatus for each of the reflectionmirrors to drive them independently.

The amount of the infrared light entering the imaging apparatus may beincreased more than the first embodiment example by disposing theinfrared light reflection mirror 5 that reflecting the infrared light tothe audience seats as the present embodiment, more specifically byreflecting the infrared light to the audience seats using the infraredlight reflection mirror 5 with a reflection ratio greater than thescreen.

Consequently, the prevention effect greater than that of a conventionalsystem may be expected. Further, the infrared light projector apparatus3 having a emission brightness (output) less than the conventionalsystem may be used when only the prevention effect comparable to that ofthe conventional system is required. Accordingly, an economical effectmay be promoted in the apparatus or its system.

Further, it is possible to realize the effect of reflecting an intenseinfrared light in a wide range by means of driving the infrared lightreflection mirror 5 or its reflection surface with the actuatorapparatus 6 and by variably changing the reflection direction of theinfrared light reflected by the reflection surface. This effect may notbe realized with the conventional system having the fixed reflectionsurface.

In the present embodiment, it is described the case that the singleplate of the infrared light reflection mirror 5 is driven so as to movethe area illuminating the reflected light. However, the followingtechnique may also be utilized. The technique is to dispose a pluralityof the infrared light projector apparatus 3 each having the differentprojection direction (incident angle with respect to the infrared lightreflection mirror 5) of the infrared light and to control them to emitone by one so as to scan the audience seat side with the reflectedlight. Alternatively, the large area may be illuminated at once byprojecting to the single infrared light reflection apparatus 5 from aplurality of the infrared light projector apparatus 3 having thedifferent projection directions (incident angle with respect to theinfrared light reflection mirror 5) of the infrared light.

(5) Fifth Embodiment Example

The fifth embodiment example is shown in FIG. 9. This embodiment exampleis related to a novel feature of enabling a recording of light imagepattern irrelevant to the main feature program with the visual imagesrecorded in the unauthorized manner by intermittently emitting theinfrared light. This embodiment may be applicable to a conventionalsystem (system in which the infrared light is projected to the screen 2from a vicinity of the projector apparatus or any other distantlocations so as that the infrared light reflected may be entered intothe imaging apparatus of a person who is conducting the unauthorizedact) as well as the above-cited embodiments or the other embodiments.FIG. 9 show an configuration example of a case in which the presentinvention is applied to the first embodiment example.

Similar to the other embodiment examples, the present embodiment may beapplicable to a home theater as well as a movie theater or any othertheater system. Of course, the visual images projected onto the screeninclude television programs and the other copyrighted products as wellas a movie. Next, a specific example of each apparatus composing thesystem shown in FIG. 9 will now be described. Here, explanations areomitted except an emission control unit 7 since they are similar to thefirst embodiment example. The same applies to case where the presentembodiment is combined with the other embodiment examples.

The most simple emission control method is an emission pattern in whichlight-on and light-off are repeated in turn with a base cycle. In thiscase, the emission control unit 7 may be realized by, for example, anoscillator, a multi-vibrator, or any other oscillation means. In suchcase, the emission control unit 7 may also be constructed with acomputer, an IC for specific purpose, or any other logic circuits. Theintermittent emission of the infrared light can cause difficulties inthe viewing even the infrared light image is not bright in the recordedvisual image since the intermittently emitted infrared light is easierto be recognized. Of course, it is possible to deteriorate the visualimage that is imaged in the unauthorized manner as much as the viewingbecomes very difficult in case that brightness of the recorded lightimage is high since a change of the brightness level may be set tolarge.

In case that more complex control is required, it is necessary to have arecording unit for an emission code (or emission pattern) indicating apredetermined information (for example output date, output location,screen number or the like) to be recorded, and an output unit forreading out an emission control information (light-on and light-off)signal according to the emission code from the recording unit to output.Of course, in order to automatically convert the emission code accordingto an arbitrary prescribed information inputted by a supervisor, it ispreferred to further include a conversion table or any other convertingmeans for converting the prescribed information to the emission code.

Further, as shown in FIG. 9, the emission control unit 7 may be anapparatus independent from the infrared light projector apparatus 3, ormay be provided inside of the infrared light projector apparatus 3composing a single unit. In case that the emission control unit 7 isprovided inside of the infrared light projector apparatus 3 composingthe single unit and a plurality of the infrared light projectorapparatus 3 are used, synchronizations among these apparatus areadopted.

Next, the other emission control methods are described. A basic emissioncontrol method is dedicated for disabling the viewing of recorded visualimages. However, a desired information may be recorded by controllingthe intermittent emission itself. Of course, the emission control unit 7controls the emission timing.

For example, as shown in FIG. 10, the desired information may beembedded along the time axis by assigning data “1” of binary code toLight-On and “0” to Light-Off in case that the emission code“10001110010” is indicating a movie theater ID of “001”. In FIG. 10, itmay be seen that 1 frame (1 field) is the minimum unit of the light-onand the light-off. However, the minimum unit required for indicatingsingle value of the emission code may be arbitrarily varied. Forexample, 0.5 second or 1 second may be used for the minimum unit. Incase that the unauthorized imaging act is performed, such light imagesare recorded so as to not only disable the viewing of the recordedvisual images but also identify a location where the unauthorizedimaging was taken place when such the recorded visual image is placed ina market. Although FIG. 10 shows a case in which single emission sourceis used, the emission control can be similarly performed with aplurality of the emission sources.

FIG. 11 shows another control method for embedding a desired informationalong the time axis. In the above cited case of FIG. 10, recordingposition of the light image is fixed (namely, the emission source isfixed). However, it is possible to transit the recording position of thelight image itself in a relay form as shown in FIG. 11. No meaning isprovided in the recording position of the light image in case of FIG.11. Also in this way, the same information as FIG. 11 may be recorded.

FIG. 11 shows the emission pattern and its recording example for a casethat four positions at four corners of the screen are assigned asrecording positions where the infrared light images are to be recordedand a rule is applied to advance the recording position of the lightimage in a clock wise direction every time the emission code valuechanges from “0” to “1”. Of course the other rules may be applied, too.For example, the following may be contemplated. The rule may include arule of advancing the recording position of the light image in aclockwise direction every time “1” is appeared in the emission code, arule of advancing the light image in a counter clockwise, a rule oftransiting the light image to a point other than the neighboring lightimage candidate point in accordance with a predetermined emissionposition transition rule, or the like.

FIG. 12 shows another control method for embedding a desired informationalong the time axis direction. FIG. 12 shows a method for realizingrecording of the information by assigning “1” and “0” of the emissioncode to combination patterns in which a plurality of the light imagesare appeared. This is an example in which the appearance position of thelight image also has meaning. FIG. 12 shows an recording example of acase in which “0” of the emission code is assigned to a combinationpattern in which two of the light images are appeared in the upper leftcorner and the lower right corner respectively, and “1” of the emissioncode is assigned to a combination pattern in which the light images isappeared only in the upper left corner. With using the control method,it is possible to identify the location where the unauthorized act wasperformed. Of course, the positions at which the infrared light image isrecorded may be positions other than the four corners of the screen, andthe combination patterns indicating each code vale may use the otherones. For example, in the above cited case, “1” of the emission code maybe assigned to a combination pattern in which two of the light imagesare appeared in the upper right corner and the lower left cornerrespectively.

FIG. 13 shows an modification example of FIG. 12. In the case of FIG.12, “0” and “1” of the emission code are assigned to the combinationpatterns of the light image. However, in this example, only single lightimage is assigned. That is, meaning is provided on the appearingposition. In FIG. 13, “0” of the emission code corresponds to the lightimage appeared at the upper left corner of the screen, “1” of theemission code corresponds to the light image appeared at the lower rightcorner of the screen. As to the synchronized control of emission timingof two light images, FIG. 13 is one of the controller of FIG. 12.

Examples described in the above are the cases where each of the lightimage patterns appeared along the time axis direction has own meaning.However, the following method may be contemplated, too. That is, themethod is to superpose information on the light image pattern itself.For example, as shown in FIG. 14, the following case may becontemplated. In such case, only a pattern of the light image positionsappeared in a predetermined time period has meaning and no meaning isattached to the transition of the light image appearance position northeir appearance order when the appearance position of the light imagetransits as time elapse. That is, FIG. 14 shows a case in which thelight image appearance position is transited “upper left corner→lowerright corner→upper left corner→lower left corner→upper left corner→lowerright corner” whereby providing meaning to a light image pattern itselfrecognized at a plane independent of the time axis (time axiscompressed). Here, the predetermined information is indicated by lightimage patterns appeared at corners excluding the upper right corner. Theemission control method intending such superposition of the informationmay also be contemplated. It is possible to contemplate an emissioncontrol method intending to use such information superposition.Alternatively, the emission may be controlled so as that the lightimages appear at three points except the upper right cornersimultaneously.

It becomes possible to record the predetermined information in additionto disabling the viewing by performing the intermittent emission controlof the infrared light like the present embodiment example, namely byintermittently projecting the infrared light image (spot light) on thescreen. Further, in case that the information is superposed on theintermittent emission itself, the light image itself may be recognizedindependent of the main feature program content or the brightness sincea large spot light that is easily recognizable may be used. On the otherhand, in case that character information is recorded by focusing theinfrared light on the screen like the conventional system, there may besome difficulties in reading out the character information depending onthe main feature program content or the brightness.

In the explanation described above, it is basically assumed that singleinformation is to be recorded (in this case the same pattern isrepeatedly appeared with a predetermined interval). However, in casethat a plurality of information are to be recorded, a control may beperformed so as to project light image patterns corresponding to thedifferent information with a predetermined interval.

(6) Sixth Embodiment Example

The sixth embodiment example is shown in FIG. 15. This embodimentexample is related to a novel feature of projecting the infrared lightonto the screen during scenes of the low brightness or for selectivelyprojecting the infrared light onto screen surface areas having lowbrightness whereby increasing the prevention effect with the infraredlight. This embodiment may be applicable to a conventional system(system in which the infrared light is projected to the screen 2 from avicinity of the projector apparatus or any other distant locations so asthat the infrared light reflected is entered into the imaging apparatusof a person who is conducting the unauthorized act) as well as theabove-cited embodiments or the other embodiments.

FIG. 15 shows an application example of a movie theater or any othertheater system. However, like the other embodiment examples, thetechnique itself may be applicable to a home theater. Of course, thevisual images projected onto the screen include television programs andthe other copyrighted products as well as a movie.

Next, a specific example of each apparatus composing the system shown inFIG. 15 will now be described. The system shown in FIG. 15 is to disposethe infrared light projector apparatus 3 at the rear side of the screenlike the system related to the first embodiment example. As to thispoint, the present embodiment example is one example of the firstembodiment example. The same projector apparatus 1 and the same screen 2are used as the first embodiment example. Of course, the same infraredlight projector apparatus 3 is used as the first embodiment example.That is, the infrared light projector apparatus 3 may be disposed notonly the rear side of the screen but also disposed in the front side ora vicinity of the screen.

However, in the present embodiment example, a plurality of the infraredlight projector apparatus 3 are provided at least as much as the numberof virtual areas assumed so as to selectively project the infrared lightonto areas on the screen having low brightness. Here, at least 28 of theinfrared light projector apparatus 3 are required since it is assumedthat the screen surface is virtually divided into 28 partial areas (4lines×7 rows). In the present embodiment, the same number of the lightsensors as the number of virtual areas, namely, 28 light sensors areprovided. A proper value is determined for the number of the partialareas for each system by considering a size of the screen 2, a size ordisposition method of the infrared light projector apparatus 3, or anyother conditions.

The light sensor 8 is means for detecting corresponding brightness ofthe screen 2 based on the projection light transmitting or passingthrough the screen 2. As the light sensor, a photodiode or aphototransistor may be used, for example. The light sensor 8 is disposedat the rear side of the screen 2. A distance from the screen 2 to theposition, at where the light sensor 8 is disposed, may differ dependingon a size of the partial area corresponding to each sensor 8. Forexample, the sensor 8 has to be disposed closely to the rear sidesurface of the screen 2 so as to detect the brightness at thecorresponding area precisely if the partial area has smaller size whilethe sensor 8 may be separated with some distance from the screen 2 ifthe partial area has larger size.

In a typical case, the light sensor 8 is disposed at a vicinity of thecenter of the corresponding partial area. This is because that adetection value of the light sensor 8 becomes a representative value ofthe brightness at each partial area. However, it is not necessary to bethe exact center of the partial area. In case a plurality of the lightsensors 8 are used for detecting brightness of single partial area, thelight sensor may not be provided at the center of each partial area.

The infrared light projector apparatus 3 or the light sensor 8 describedabove may be disposed relatively arbitral position when a speaker is notprovided in the rear side of the screen. However, when the speaker isdisposed at the rear side of the screen, the infrared light projectorapparatus 3 or the light sensor 8 has to be disposed so as not tointerfere the replay operation.

The infrared light projector apparatus 3 and the light sensor 8described above may be disposed separately as independent apparatus, ormay be disposed as an emission unit in an integral body as shown in FIG.16. In a case of FIG. 16, the infrared light projector apparatus 3 is anunit apparatus in which a plurality of the infrared light emittingdevices 3A (here, six units) are arrayed in a single plane. The lightsensor 8 is disposed at a vicinity of the center of the infrared lightprojector apparatus 3. Such infrared light projector apparatus 3 may bedisposed at each partial area of FIG. 15.

Further, the light sensor 8 outputs detection signals (for example,current value, voltage value) S2 in accordance with the correspondingscreen brightness. Such detection signal may be an analog signal ordigital signal. In a case of FIG. 16, a control signal S3 controllingthe emission of the infrared light emitting device 3A is sent to theinfrared light projector apparatus 3 from the infrared light projectorcontrol apparatus 10.

The shutter sensor 9 is an effective device in case that the projectorapparatus 1 is a film-type projector apparatus. Accordingly, in casethat a digital signal type projector is employed for the projectorapparatus 1, such shutter sensor 9 does not exist in its configuration.Here, the shutter sensor 9 is used so as to project the infrared lighton the screen during periods in which a shutter of the film-typeprojector apparatus (so-called a cinema projector) shields theprojection light. That is, the shutter sensor 9 is used for detectingthe periods or timings during which the shutter is closed and the screenbrightness is decreased.

FIG. 17 shows a representative configuration example of the presentfunction. The cinema projector projects visual images on the screen byrepeating an operation of projecting the visual images onto the screenby radiating a light-source light 12 when a film 11 stays still at anaperture (film projection window of the projector) and an operation ofshielding the light-source light 12 radiated on the film 11 to transferthe frames during the shielding period. A lens 14 in this figure is aprojection lens to project the light-source light to the screen 2.

In general, a circular plate having cut sections is employed as theshutter 13 used for shielding the light-source light. Typically, thesecut sections may be provided at two position at opposing angles of thecircular plate. Typically, the circular plate rotates 24 times persecond, and shields the light-source light twice in every one frame(FIG. 18(B)). An inter-sprocket 15 transfers the film 11 for one frameduring one of two shielding periods which appear twice per frame toshield the light-source light (FIG. 18(A)). The infrared light projectorapparatus 3 coupled with the motion timing of the shutter 13 projectsthe infrared light twice per frame (FIG. 18(C)).

As the shutter sensor 9, not only an optical type but also an electronicor mechanical type may be contemplated. For example, as the opticaltype, a method shown in FIG. 19 may be contemplated. FIG. 19 is themethod for determining a positional relationship (rotational position)in which the shutter 13 shields the light-source light by detectinglight flux reflected at the shutter surface. FIG. 19(A) shows a state inwhich the light-source light 12 is projected, 19(B) shows a state inwhich shielding of the shutter 13 is started, FIG. 19(C) shows a statein which the shutter 13 is shielding light-source light 12.

In case that the method of FIG. 19 is used, the shutter sensor 9 may bedisposed so as that the shutter 13 is faced with a vane during theshielding of the light. As the shutter sensor 9, a light emitting diode(emission means) and a photo diode (light reception means) disposed at aplane facing the shutter 13 may be used. According to thisconfiguration, the positional relationship of the shutter may bedetected since an amount of light received by the photodiode is highduring the shielding of the light-source light and the amount of lightis low during the projection.

As the optical type method, there is a method for detecting thepositional relationship (rotational position) of the shutter 13 bydisposing the light emitting diode and the photodiode so as to face eachother sandwiching the circular plate's rotation area and determiningwhether the light emitted from the light emitting diode is detected bythe photodiode. In this case, the rotational position of the circularplate may be detected based on a light receiving timing and a lightshielding timing of the light emitted to the photodiode from the lightemitting diode.

Alternatively, a method for mechanically detecting a rotational positionof the circular plate may be employed for the shutter sensor 9. Forexample, it is possible to mechanically detect the shutter's rotationalposition from a rotational position (position of gear) of a gearattached to a rotational axis so as to have the same axis. Further, forexample, the following method may be contemplated. The method is fordetecting whether the cut section or the circular plate's vane ispositioned from a change in an electrostatic capacitance betweenelectrodes disposed so as to sandwich the rotational area of thecircular plate. Further, a method for detecting the shutter's rotationalposition from a drive information itself of the rotational axis.

Of course, the shutter sensor 9 in accordance with a form or a type ofthe shutter may be employed in case that the form or the type of theshutter may differ. For example, in case that open-close of the shutteris electronically controlled, it is possible to use a method fordetecting a period of the light-source light shielding using theopen-close signal.

The following methods may be contemplated as an utilizing method of thedetection results. The methods includes a method for emitting theinfrared light when the shutter's close motion is detected and a methodfor forecasting the shutter's close motion from the detection result andemitting the infrared light at a forecasted timing.

The infrared light projector control apparatus 10 is a mean forcontrolling the emission of the infrared light projector apparatus 3(each infrared light emitting device 3A in the configuration of FIG. 16)according to a light sensor output S2 outputted from the light sensor 8or a shutter information S4 outputted from the shutter sensor 9.

An internal configuration of the infrared light projector controlapparatus 10 may differ depending of a system to which the infraredlight projector control apparatus 10 is to be applied. For example, acomputer (having a processing unit (having a controller and an operationdevice), a memory, an input/output unit) is generally used in case thatthe system has a configuration for simultaneously controlling all of theinfrared light projector apparatus 3 as shown in FIG. 15. However, it isalso possible to realize functions of programs executed by the computeras electronic circuits.

However, the infrared light projector control apparatus 10 may not berequired for every case. For example, a desired prevention effect may berealized without using the control apparatus by directly using detectionresults of the light sensor 8 as a light amount adjusting signal for theinfrared light projector apparatus 3 to increase an amount of theinfrared light in a scene or area in which the screen is dark. Here, itis assumed that the detection result changes in analog form.Alternatively, a multi-valued information may be outputted as the lightamount adjusting signal in case that the light sensor has a function ofconverting the analog signal to the digital signal.

For example, it is possible to configure a system capable of switchingthe infrared light projection and non-projection by directly inputtingthe detection results of the light sensor 8 into the infrared lightprojector apparatus 3 in case that the light sensor 8 has a function ofdetermining whether the screen brightness is brighter than apredetermined reference value or not (in case that it has a comparisonfunction of comparing the detection results and the predeterminedreference value). Of course, the infrared light is projected in casethat the screen brightness is equal or less than the predeterminedreference value.

For example, a desired prevention effect may be realized without usingthe control apparatus by using the detection result of the shuttersensor 9 as an on-off control signal of the infrared light projectorapparatus 3 and projecting the infrared light at a time of the frametransfer at which the screen becomes dark.

An explanation comes back to a case in which the infrared lightprojector control apparatus 10 is used. For example, the infrared lightprojector control apparatus 10 commands the infrared light projectorapparatus 3 to project the infrared light by outputting the controlsignal S3 when the shutter's close motion (namely the infrared light isshielded) is detected by the shutter sensor 9. Here, the infrared lightprojector control apparatus 10 may command all of the infrared lightprojector apparatus (in case of FIG. 15, it is possible to command all28 units of the infrared light projector apparatus to project).Alternatively, the infrared light projector control apparatus 10 maycommand a part of the infrared light projector apparatus to project theinfrared light. For example, in case of FIG. 15, it may command theprojection of the infrared light so as that the emission pattern becomesa check pattern. Alternatively, it is also possible to command theprojection of the infrared light so as that the emission pattern formsan other recognizable graphic pattern (may include character ornotation).

In case that the infrared light projector control apparatus 10 isconfigured as a group of plural infrared light emitting devices as shownin FIG. 16 and the projection command of the infrared light is sent tothe infrared light projector control apparatus 10, there may be a casethat the emission is ordered to all of the infrared light emittingdevices as shown in FIG. 20(A), and a case that the emission is orderedto a part of the infrared light emitting devices as shown in FIG. 20(B).A more complex graphic pattern may be recorded by combining the otheremission pattern of the neighboring infrared light projection apparatus10 by controlling the emission of the infrared light emitting devices asshown in FIG. 20(B).

Next, a control operation example will now be explained for a case thatthe detection result of the light sensor 8 is inputted into the infraredlight projector control apparatus 10. The most simple control method isa method for judging the screen brightness based on the detection outputof the light sensor 8 and emission-controlling the infrared lightprojector apparatus 3 assigned to an area to be monitored by the lightsensor when the brightness is a lower than the predetermined brightness.Of course such control function may be realized by means of software orhardware.

In case that the judgment process is executed in digital manner, theinfrared light projector control apparatus 10 may be constructed to havea memory (memory means) for recording a threshold value to be acomparison reference value, a comparator (comparison means) forcomparing an input value (value converted by means of converting to adigital signal in case outputs of the light sensor is the analog signal)and the above-cited threshold value, and an output unit (output means)for outputting the comparison result to corresponding infrared lightprojection apparatus 3. On the other hand, in case that the judgmentprocess is executed in analog manner, the infrared light projectorcontrol apparatus 10 may be constructed to have a comparison circuitstage of a differential amplifier circuit configuration for comparingthe light sensor input and a reference value (for example, generated byresistance divided voltage), and an output stage for outputting thedifferential output.

Here, the threshold value may be determined, for example, based onmeasured values or empirical values with consideration of recordingcharacteristics of the imaging apparatus (for example, opticalcharacteristic of a solid state imaging apparatus) or visual sensecharacteristic of human being. In case that a disposition density of thelight sensor is relatively high, the infrared light emission does notbring much effect at the low brightness region when an output from aspecific light sensor indicates relatively low brightness while anoutput from the other light sensors in the vicinity indicate highbrightness. Accordingly, it is possible to control not to emit theinfrared light when such condition is satisfied.

Even in case that the infrared light is selectively projected on to thescreen areas having the low brightness, the following method may becontemplated. The method is for emitting only a part of the infraredlight emitting devices corresponding to the area as shown in FIG. 20(B).In this case, a memory for recording a predetermined emission patternand program steps for generating the emission pattern are added to theprevious configuration.

The control operation described above is an operation example for a casethat only one light sensor 8 is basically disposed in an area in whichthe infrared light is to be projected. However, the following operationmethod may be employed in case that a plurality of the light sensors aredisposed in the area in which the infrared light is to be projected. Thearea in which the infrared light is to be projected may be each of thepartial areas of FIG. 15, or may be a plurality of the partial areas(Maximum is a whole area of the screen).

In the following, an explanation is given in case that the whole area ofthe screen is considered to be the infrared light projection area sincethe control operations themselves are the same. That is, it will now beexplained how 28 detection results are used to generate a projectioncommand of the infrared light as shown in FIG. 15.

For example, there is a method for using the number of the light sensors8, by which the low screen brightness are detected, as a judgmentreference. The same methods described above may be applied directly herefor judging whether the brightness is low or not.

In this case, the infrared light projector control apparatus 10 comparesthe predetermined threshold value stored in the memory and the detectedvalue counted at every time-point counted by a counter (the number ofthe light sensors judged as the low brightness) with the comparator, andissues the emission command to project the infrared light on the wholescreen which is the area to be projected when the detected value isbigger than the predetermined threshold value. In case that apredetermined pattern is to be formed from a plurality of light images,the infrared light projector control apparatus 10 issues the emissioncommand only to the infrared light projection apparatus corresponding tothe pattern. In this case, the infrared light projector controlapparatus 10 identifies positional information of the infrared lightprojection apparatus corresponding to a predetermined pattern by readingout the recording apparatus, or identifies positional information of theinfrared light projection apparatus corresponding to a predeterminedpattern by calculation.

Regarding to the judgment reference, there is a method for using aposition of the light sensor 8 that detected the low screen brightness.For example, there is a method for using the output of the light sensor8 disposed in a vicinity of the screen center as an object to be judged.There is an advantage of ascertain the recording of the infrared lightat the center part of the screen since a vicinity of the screen centeris visually a highly visible part. Alternatively, there is a method forusing the output of the light sensor 8 disposed in a vicinity of thescreen surrounding (for example, screen's outer periphery, one of fourcorners, all of four corners, or the like) as an object to be judged.Although the prevention effect may be limited at the screen surroundingcompared to the center part, a certain prevention effect may beanticipated since the rest of the area (including the screen center) isoften also dark when the surrounding to be judged is dark. Further,ample prevention effect may be realized by letting the infrared lightimages appear very often even the appearance position is at thesurrounding.

Further, for example, the following method or the like may becontemplated. The method is for using the output of the light sensor 8disposed at a plurality of judgment points set up on the screen (forexample, five points comprising four corners of the screen and thecenter part) as objects to be judged. Although it depends on the numberof the measurement points and a set-up method, the infrared light may beprojected at least on the dark area of the screen. In case of fixing thejudgment point as described above, the light sensors 8 may be disposedonly at these judgment points.

In the above described example, the emission of the infrared light isbasically controlled by judging whether the low brightness is detectedat the judgment area or point. However, in case that a plurality of thelight sensors 8 are disposed at single judgment area or point, thejudgment of the low output may be performed regarding to the judgmentarea or point only when the number of the light sensors, from which thejudgment of the low brightness is obtained, is larger than apredetermined number.

In the above described example, the detection results regarding thejudgment points are used as judgment elements. However, the judgment onwhether the infrared light should be projected or not may be performedbased on a distribution pattern of the light sensors in which thejudgment result of the low brightness is obtained while using all thelight sensors disposed at the rear side of the screen as the judgmentelements. In this case, there are provided a distribution pattern fortriggering the infrared light projection and a distribution pattern fornot triggering the infrared light projection, or, one of thosedistribution patterns. And the judgment of whether the infrared light isprojected or not may also be performed according to a degree ofcoincidence with the distribution pattern.

The infrared light projector control apparatus in this case may furthercomprises a memory for recording the distribution pattern for thejudgment, a distribution pattern recording an actual measurementdistribution pattern of the light sensors in which the detection resultof the low brightness is obtained, and a judgment unit for judging thedegree of coincidence between these.

Of course, in case that the infrared light projection is performed as aresult of the judgment, the above cited techniques may be applicable tooperations for forming a predetermined pattern from the a plurality ofthe light images.

As in the present embodiment example, it is possible to ascertain therecording of the infrared light into the imaging apparatus of a personconducting the unauthorized act by selectively projecting the infraredlight onto scenes or areas in which the screen brightness is low sincethe infrared light is projected onto the scenes or areas in which thebrightness of the infrared light images becomes certainly higher thanthe visual images of the main feature program. Particularly, in casethat the area to which the individual light image is projected islimited to a relatively small area as shown in FIG. 15, an output levelmay be a small value in the infrared light projector apparatus itselfsince the brightness of the light image on the screen may be increasedas much as the spreading of the light flux is tightened.

Further, it is possible to prolong the product life time and the powerconsumption since the infrared light is emitted only in the scene orarea in which the prevention effect is discernible.

(7) Seventh Embodiment Example

The seventh embodiment example is shown in FIG. 21. This embodimentexample is a modification example of the sixth embodiment example.Accordingly, the same applies to points of projecting the infrared lightonto the scene in which the screen brightness is low or selectivelyprojecting to the area of the screen surface in which brightness is low,in order to increase the prevention effect of the infrared light.

However, the present embodiment example and the sixth embodiment exampleare different in a method for acquiring information regarding the sceneor time-point in which the screen brightness decreases. That is, thepresent embodiment example differs from the sixth embodiment example ona point of acquiring information of time-point in which an averagebrightness of the screen decreases (time information) or informationregarding partial area and time-point in which the screen brightnessdecreases (namely, position information and time information), from arecording medium or via a network.

Accordingly, no light sensor is required in the present embodimentexample. The basic configuration is the same as the sixth embodimentexample. Accordingly, the screen configuration and the disposition ofthe infrared light projector apparatus are similar to the sixthembodiment example. Although the infrared light projector apparatus 3 isdisposed in the rear side of the screen 2, the projection may also bedone from the front side of the screen 2.

A program server 16 is an apparatus to output visual image data S5 tothe projector apparatus 1. Here, there may be cases that the visualimage data S5 is data read out from a recording medium 17 (for example,video tape, CD-ROM, DVD or the like) or that the visual image data S5 isdata being distributed via a network 18. However, such visual image dataS5 is not outputted in case that the projector apparatus 1 is a filmtype projector apparatus.

The program server 16 also functions as an apparatus replaying the timeinformation or the position information of the partial area suited forprojecting the infrared light from the recording medium 17, or receivingthose information via the network 18. That is, the program server 16also functions as an apparatus outputting an infrared light projectioncontrol data S6 to the infrared light projector control apparatus 10.The recording medium may be one provided through a mail service or apackage delivery service, or one recording data distributed via thenetwork 18 in advance.

Here, a synchronization between the visual image data S5 to be outputtedto the projector apparatus 1 and the infrared light projection controldata S6 to be outputted to the infrared light projector controlapparatus 10 is performed by the program server 16. Of course, in casethat the digital type projection system as shown in FIG. 21, thesynchronization between data is controlled based on the commonsynchronization information or the time information for reproduction. Incase that the projector apparatus 1 is the film type, an output timingof the infrared light projection control data S6 is controlled based onthe synchronization signal or the position information read out from thefilm, or the rotational position information of the shutter 13.

The following cases may be contemplated for the infrared lightprojection control signal S6. The case may be a case in which theinfrared light projection control signal S6 includes only the time-pointinformation wherein the screen brightness decreases (time information),a case in which the infrared light projection control signal S6 includesthe partial area and the time-point information wherein the screenbrightness decreases (namely, position information and timeinformation), or a case combining these cases.

For example, in case the projector apparatus 1 is a digital typeapparatus, it is possible to contemplate that the infrared lightprojection control data S6 may be information of a time-point in whichthe light-source light is shielded with the shutter 13, information of apre-detected time-point in which an average screen brightness decreases(depending on contents of the visual images), information of apre-detected time-point in which the screen brightness decreasespartially (depending on contents of the visual images).

Alternatively, in case the projector apparatus 1 is a digital typeapparatus, it is possible to contemplate that the infrared lightprojection control data S6 may be information of a pre-detectedtime-point in which an average screen brightness decreases (depending oncontents of the visual images), information of a pre-detected time-pointin which the screen brightness decreases partially (depending oncontents of the visual images).

The infrared light projector control apparatus 10 is means forspecifically controlling the emission of the infrared light projectorapparatus 3 in practice. As similar to the sixth embodiment example, theinfrared light projector control apparatus 10 may command all of theinfrared light projector apparatus 3 to project the infrared light, or,may command only a part of the infrared light projector apparatus 3 toproject the infrared light. Of course, in case the infrared lightprojector apparatus 3 is configured as a group of plural infrared lightemitting devices as shown in FIG. 16, all of the plural infrared lightemitting devices may be emitted, or, only a part of them may becontrolled to emitted.

Also in the present embodiment example, it is possible to ascertain therecording of the infrared light into the imaging apparatus of a personconducting the unauthorized act by selectively projecting the infraredlight onto scenes or areas in which the screen brightness is low sincethe infrared light is projected onto the scenes or areas in which thebrightness of the infrared light images becomes certainly higher thanthe visual images of the main feature program. Particularly, in casethat the area to which the individual light image is projected islimited to a relatively small area as shown in FIG. 21, an output levelmay be a small value in the infrared light projector apparatus itselfsince the brightness of the light image on the screen may be increasedas much as the spreading of the light flux is tightened.

Further, it is possible to prolong the product life time and the powerconsumption since the infrared light is emitted only in the scene orarea in which the prevention effect is discernible.

(8) Eighth Embodiment Example

The eighth embodiment example is shown in FIG. 22. This embodimentexample relates to a novel feature of increasing the amount of theinfrared light reflected at the screen surface to an value more thanthat of an conventional system by disposing the infrared light projectorapparatus 3 at a vicinity position in the front side of the screen andprojecting the infrared light to the screen from the infrared lightprojector apparatus 3.

FIG. 22 represents a composite system comprising the present embodimentand the above described sixth embodiment example (the novel feature ofcontrolling the emission timing of the infrared light base on theshutter information) or the above described seventh embodiment example(the novel feature of controlling the emission timing of the infraredlight base on the infrared light projection control data).

Further, the present embodiment example is an application example of anovel feature of automatically adjusting the infrared light projectingdirection in accordance with a change of the screen size depending onthe contents.

FIG. 22 also shows an example applicable for a movie theater or othertheater systems. Of course, as similar to the other embodiment examples,the technique itself may be applicable to a home theater. In any cases,the visual images projected onto the screen include television programsand the other copyrighted products as well as a movie.

First, a disposition method of the infrared light projector apparatus 3,that is unique for the present embodiment example, may be explained. Forexample, as shown in FIG. 22, the infrared light projector apparatus 3is disposed somewhat front side of the screen periphery part (forexample, screen frame or outer border area). In this case, the infraredlight is projected within a range from an angle close to the horizontaldirection to an angle close to the vertical direction depending on aprojection position on the screen surface, and the infrared lightrandomly reflected on the screen or the like incident into the imagingapparatus of a person conducting the unauthorized act. The incidentangle of the infrared light is determined according to a size of thescreen 2 or the disposition location of the infrared light projectorapparatus 3, and not limited to any particular ranges.

FIG. 22 shows eight units of the infrared light projector apparatus 3disposed along the top and the bottom rims for the longer rims(transversal direction) and five units of the infrared light projectorapparatus 3 disposed along the right and the left rims for the shorterrims (vertical direction). However, the infrared light projectorapparatus 3 may be disposed along only one of the rims, or the infraredlight projector apparatus 3 may be disposed along any two arbitraryrims, or the infrared light projector apparatus 3 may be disposed alongany three arbitrary rims. Of course, any arbitrary number of theinfrared light projector apparatus 3 may be disposed.

In case that the infrared light projector apparatus 3 is disposed in avicinity of the screen 2, the infrared light projector apparatus 3 maybe disposed at not only the screen periphery part but also a pointcloser to the screen than the midpoint of the projector apparatus 1 andthe screen 2. For example, the disposition location of the infraredlight projector apparatus 3 may be at L/3, L/4, L/5 from the screenwhere L is a distance between the projector apparatus and the screen.

Next, characteristic apparatus among the system shown in FIG. 22 willnow be explained. Explanations of the other apparatus examples areomitted since those are common to the other embodiment examples. Thereare two characteristic apparatus. Those are a projector directingactuator apparatus 19 and a screen mask switching apparatus 20. Thoseare apparatus for auto-adjusting a projection position or direction ofthe infrared light automatically coupled to the switching of the screensize in case that there are a plurality of the screen sizes suited forthe projected visual images.

FIG. 23 shows an attachment example of the infrared light projectorapparatus 3 to the projector directing actuator apparatus 19. FIG. 23represents a state in which the projector directing actuator apparatus19 is turnably attached on the backside of the infrared light projectorapparatus 3 (opposite side to the infrared light projecting direction).Here, the turning axis is orthogonal to the optical axis. The infraredlight projector apparatus 3 is coupled to the projector directingactuator apparatus 19 through a motor and a gear, and attached so as toturn a predetermined angle in a predetermined direction in accordancewith an amount of the motor rotation.

The actuator apparatus is not limited to a technique transferring powerby an amount of rotation but also one transferring the power with anamount of linear motion. Further, the infrared light projector apparatus3 may be an object to be directly driven by the actuator apparatus, ormay be an object to be indirectly driven through a gear or rubber or anyother coupling devices by the actuator apparatus. In case of FIG. 23,the moving direction is only one. However, it may be constructed to havetwo movable directions. For example, it may have two movable directions,the horizontal direction and the vertical direction.

The screen mask switching apparatus 20 is means for automaticallyproviding an actuator control information of the infrared lightprojector apparatus to the projector directing actuator apparatus 19according to a command of the screen size switching. For example, thescreen mask switching apparatus 20 comprises a memory unit for recordingscreen sizes and information regarding a projecting direction of eachinfrared light projector apparatus suited for the corresponding screensize (for example, information regarding projecting direction or angle),and a control unit reading out a numerical value suited for the screensize after the switching from the memory unit and outputting thenumerical value to each position of the projector directing actuatorapparatus 19. Alternatively, the information to be outputted to theprojector directing actuator apparatus 19 may be provided by calculatingan adjusting amount with respect to the current value (differentiationvalue) in case that a target value (optimum value) itself is notprovided like the present example. One of these data may be outputted asa control data S7 from the screen mask switching apparatus 20 to theprojector directing actuator apparatus 19.

The switching command of the screen size or the optimum screen sizeinformation may be provided in conjunction with a manual operation of anoperator in one case, or may be automatically provided based oninformation recorded in association with a visual image content in theother case. For example, in case of a movie theater, a person in chargeat the theater side operates a button to change a position of a blackoutcurtain (mask) when the screen size (aspect ratio) is switched. Suchbutton operation may be shared for switching the projecting direction.In case the recorded information is used as in the latter case, it ispossible to contemplate a case in which the optimum information isrecorded in a medium recording the visual image contents, and the othercase in which a corresponding chart is recorded in the other recordingmedium separated from the visual image contents.

Although FIG. 22 shows the projector directing actuator apparatus 19 andthe screen mask switching apparatus 20 as separated apparatus, these maybe constructed as single apparatus. Further, the adjustment of theinfrared light projecting direction may be done not only for individualinfrared light projector apparatus but also for a row unit or a unit ofneighboring plural infrared light projector apparatus.

It is possible to further increase the prevention effect against theunauthorized imaging act since an amount of the reflection light may beincreased remarkably in comparison with an conventional system byprojecting the infrared light to the screen from the vicinity positionof the screen so as that the reflected light may be incident into theimaging apparatus of a person conducting the unauthorized act, as in thepresent embodiment example. Further, an effect of deteriorating thequality of visual images imaged in the unauthorized manner may bepromoted by combining the technique of selectively projecting theinfrared light onto the scene where the screen brightness decreases orthe area of the low brightness. Of course, it is possible to ascertainthe recording of a desired information by combining the intermittentprojection or the selectively projection techniques at a time ofinfrared light projection.

Further, it is possible to effectively avoid an event in which theinfrared light is projected at outside of the visual image contentprojecting area by automatically adjusting the infrared light projectingdirection according to the screen size, as in the present embodimentexample. Namely, it is possible to increase the prevention effect bymost effectively utilizing the available infrared light projectorapparatus.

In the above, the explanation is given to a composite system comprisinga portion projecting the infrared light from the front side vicinity ofthe screen, a portion relating the automatic adjustment function of theprojecting direction, and a portion relating to selective projectiontechnique at the low brightness area or scene. However, it is possibleto contemplate a system configuration including only the portionprojecting the infrared light from the front side vicinity of thescreen, or a system configuration including only the portion relating tothe automatic adjusting function of the projecting direction.

(9) Ninth Embodiment Example

In each of the above described embodiments, representative examples aredescribed for the specific examples of the conceptual embodimentexamples. However, it is possible to contemplate various embodimentexamples such as composite systems of the above described embodimentexamples or modification examples or the like.

According to the embodiments according to the present inventiondescribed in the present specification, the following effects may berealized.

(A) It is possible to have projected infrared light effectively incidentinto imaging apparatus of a person conducting the unauthorized act sinceinfrared light is projected to a viewer/audience direction from one ormore infrared light projector apparatus disposed at a screen side toallow the infrared light incident into the imaging apparatus of a personconducting the unauthorized act. Accordingly, the embodiment may produceample prevention effect even when the low power infrared light projectorapparatus is used.

(B) It is possible to have projected infrared light effectively incidentinto imaging apparatus of a person conducting the unauthorized act sinceinfrared light is actively reflected by an infrared light reflectionmirror so as that the reflected infrared light incident into imagingapparatus of a person conducting the unauthorized act. Accordingly, theembodiment may produce ample prevention effect even when the low powerinfrared light projector apparatus is used.

(C) Following effects may be realized by intermittently emittinginfrared light. For example, a location in which the unauthorized actwas taken place may be identified from the image obtained through theunauthorized manner by outputting the infrared light in accordance witha predetermined information. For another example, the viewing may becomevery difficult due to rapid change of brightness level by frequentlychanging emission intensity of infrared light.

(D) Prevention effect may be intensified further by selectivelyprojecting onto a part of the screen surface, in which brightness islower (for example, area or time period having a brightness of thescreen surface equal or less than a predetermined value) wherebyincreasing relative effects of the infrared light. Further, in case thatcertain information is superposed on the infrared light, suchinformation may be surely recorded.

(E) Prevention effect may be intensified further by projecting infraredlight to the screen from at least one or more infrared light projectorapparatus disposed in the vicinity of the screen whereby significantlyincreasing an amount of infrared light reflected on the screen, whichmay be incident into imaging apparatus of a person conducting theunauthorized act.

While the present invention has been particularly shown and describedwith reference to the embodiments according to the present invention, itwill be understood by those skilled in the art that combination of theembodiments and/or other changes in form and details can be made thereinwithout departing from the essential character thereof.

What is claimed is:
 1. An imaging prevention method for interferingunauthorized imaging of a number of visual images projected on a screen,the imaging prevention method comprising: directly projecting infraredlight to a viewer/audience side from at least one or more infrared lightprojector means, whereby enabling said infrared light to be incidentinto imaging means of a person conducting the unauthorized act so as toadversely affect unauthorized copying operations being performed by saidimaging means.
 2. An imaging prevention system for interferingunauthorized imaging of a number of visual images projected on a screen,the imaging prevention method comprising: at least one or more infraredlight projector means for projecting infrared light so as said infaredlight is directly incident into imaging means of a person conducting theunauthorized act so as to advertisely affect unauthorized copyingoperations being performed by said imaging means; and control means forcontrolling said at least one or more infared light projector means.